Some standard content:
National Standard of the People's Republic of China
Specifications lor precise engineering survey1 Subject content and scope of application
GB/T 15314.-: 94
This standard specifies the layout principles, grades, operation requirements and data processing methods of precision engineering survey and its control network. This standard is applicable to the precision survey work in the survey and design, construction layout, installation and commissioning, and deformation monitoring stages of various types of projects. When applied in other fields, its principles can also be referred to for implementation. 2 Referenced standards
GB12897 National and second-class leveling measurement specifications GB/T12979 Close-range photogrammetry specifications
3 General
3.1 Precision engineering survey is the modern development and extension of civil engineering survey. It uses advanced measurement methods, instruments and equipment to carry out measurement work under special conditions with absolute measurement accuracy reaching millimeter level and relative measurement accuracy reaching 1×10\. Precision engineering surveying accurately determines the coordinates and elevations of control points and working points, and performs precise orientation, precise alignment, and precise multiplication, serving economic construction, national defense construction, and scientific research.
3.2 The coordinates of the control points of precision engineering surveying are projected using the Gauss-Kerrings projection arbitrary band (or 3° band) plane rectangular coordinate system. The average elevation surface of the survey area or the elevation surface of the main equipment (or compensation elevation surface) is used as the projection. Under the engineering design benchmark, the coordinates of a point in the national control network and the azimuth of a side can be selected as the starting data of the precision engineering mask network. The elevation of the control points of precision engineering surveying adopts the normal height system and the 1985 national standard or standard. When the normal height difference of the working point on the level surface in the engineering area exceeds the engineering allowable error, the regional gravity height system should be used. The gravity of the engineering benchmark point must be measured, and the mean error relative to the starting gravity point shall not exceed ±1 mGal.
3.3 Precision engineering surveying uses the mean error of the relative position of adjacent points or the relative position accuracy in a specific direction as the accuracy index, and is divided into levels 1, 2, 3, and 4. Level 1 precision engineering surveying should be carried out under controllable observation conditions. Level 3 precision engineering surveying should choose the best field conditions for operation. Different accuracy indicators can be selected for different observation items in the same project. If there are control points with different accuracy requirements in the surveying project, the highest accuracy index should be selected to arrange the control points uniformly. 3.4 Precision engineering surveying technology should be coordinated with the overall design of the project. Precision engineering surveying designers must work closely with other professionals in the project to understand the purpose, characteristics, overall layout and relationship with the surrounding environment of the project; understand the structure, construction steps, progress and methods of the project; understand the overall and partial requirements of the project for the surveying work (including accuracy, time limit, etc.); collect and analyze existing surveying and mapping data and geological, hydrological and meteorological data related to the construction of the project. Designers should use mathematical programming methods combined with on-site surveys to design the best surveying technology solutions for each stage of the project construction. 3.5 The installation and positioning of engineering layout and equipment components are based on precise engineering measurement control points. The design position of the component positioning mark should be linked to the control point in the simplest and most accurate way. The installation extension work should be carried out directly using the centering device. If it is really difficult, the control point should be as close to the design position of the tree as possible. The components can be installed to the design position by using the reference line method, the chord offset method, the distance or force intersection method. The National Technical Supervision High-level 1994-12-22 approved 1995-10-01 implementation
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designed position. According to the layout method and the equipment conditions, the allowable error of the layout measurement should be reasonably determined to ensure the required accuracy of the target point. Before the component is installed, the control point should be checked and measured. After the final installation, all components should be measured for completion. 3.6 Deformation measurement of precision engineering buildings (structures) should be carried out continuously using an automated information telemetry system. It can also be carried out using a periodic re-measurement method. The re-measurement period should be determined based on the characteristics, rate, and measurement accuracy of the building (structure) deformation. If there are special requirements for deformation measurement accuracy, monitoring can be carried out in accordance with the deformation measurement specifications of the relevant profession. 3.7 Various measuring rods, wire rulers, distance meters, and leveling scales used in precision engineering measurement should be sent to an inspection agency with metrology certification for length verification. Measuring instruments, equipment, and physical and meteorological instruments used in engineering measurement should also be verified according to relevant procedures. If conditions permit, a metrology station should be established in large-scale precision engineering sites. 3.8 After the precision engineering measurement work in the construction phase is completed, the results should be submitted in a timely manner. Check, accept and write the engineering surveying technical summary and completion report. Precision engineering surveying management departments with conditions should establish an engineering surveying information database system. 3.9 In addition to applying the methods proposed in this specification, precision engineering surveying work shall give priority to the use of mature new surveying technologies and data processing methods (such as Appendices L and M) on the principle of meeting the requirements of engineering construction. If the accuracy requirements proposed by the user exceed the indicators of this specification, other methods and instruments that have been tested in practice may be used for random measurements. 4 Precision Engineering Horizontal Control Network
4.1 The main function of the precision engineering horizontal control network is to provide precise horizontal control points and corresponding control measurement data for precision engineering construction layout, equipment installation, calibration and completion measurement.
b. For the ground, buildings and main components or systems Systematic deformation monitoring provides basic data for analyzing, verifying and studying horizontal deformation. r, Provide a unified and complete precision control measurement foundation for different buildings in the same process or different groups of the same building in phased construction
d Realize the conversion between the engineering design coordinate system and the control measurement coordinate system. 4.2 Design principles of precision engineering horizontal control network 4.2.1 The accuracy of the precision horizontal control network is reasonably determined based on the requirements of the allowable error of the completed position of the key parts of the precision engineering and the actual situation through comprehensive analysis.
4.2.2 The accuracy of the precision engineering horizontal control network is generally based on the mean error (or relative change) of the relative positions of adjacent points as the basis for design. The precision horizontal control network is usually an independent network under a fixed base (the monitoring network is sometimes excluded The level of the control network generally does not have the meaning of the upper network controlling the lower network, but has the meaning of point coordination and precision matching, but it is also allowed to develop step by step. 4.2.3 The graphics of the precision engineering horizontal control network mainly depend on the engineering tasks and field conditions. It is generally composed of basic graphics such as baselines, triangles, geodetic quadrilaterals and midpoint polygons. According to the situation, it can be arranged into baselines, angle networks, two-side networks or progressive angle networks. GPS networks can also be used to establish relative horizontal control networks using the double-cheek receiver carrier phase method. The precision engineering horizontal control network generally does not make specific requirements on the network shape (including side length and angle).
4.3 Levels of precision engineering horizontal control networks
Using the relative position error of adjacent points as the accuracy index, it is divided into levels one, two, three and four (see Table 1). Table 1
Relative mean error of adjacent points
Relative mean error of position can be calculated according to the major and minor semi-axis of relative position error circle or the mean error of relative coordinate increment:
GB/T 1531494
M., ---Imi + ma.
Where: A,--the major semi-axis of relative position error ellipse, mm B,--the minor semi-axis of relative position error ellipse m; ma - the mean error of relative coordinate increment, mm It can also be calculated by the inverse mean error of length and the mean error of azimuth according to the following formula: M, =I Vm +(m X s/p))
Where: m - the mean error of side length, mm
m. - the mean error of azimuth, \):
s - side, mm;
P - 206 265\
4.4 Data to be collected before the technical design of the precision engineering horizontal control network (2)
a. Topographic maps, traffic maps, geological structure maps, hydrological data, meteorological data, etc. of various scales within a certain range of the project area. b. General engineering planning map, general building layout map, construction map, progress table and other relevant technical documents. In particular, the substantive significance of the accuracy requirements for engineering measurement should be clarified and confirmed with technical documents. ℃. Existing control measurement data, including leveling control network, business process control network, point record, results table, technical summary: 4.5 Design method of precision engineering horizontal control network The horizontal control network adopts computer-aided optimization design method (simulation method or comprehensive method used in conjunction with analytical method). The optimization design mainly includes graphic design, observation scheme design and old network reconstruction design: Regardless of the design, the quality of the horizontal control network must meet the accuracy requirements. The reliability standard, cost standard and sensitivity standard of the control network and the monitoring network must also be taken into account. 4.6 Technical design procedure of precision engineering horizontal control network a. On the general construction plan:Or the engineering design surface drawing shows the key points and lines of the building according to the scale. . According to the current construction situation and technical cases, the control points are selected on the drawing and connected into a network. . Use the computer-aided optimization design method to design multiple schemes, and select the best design scheme from them to select the site, determine the point location and the type of the pier, and ensure the line of sight. It is also necessary to consider the geological conditions, groundwater level, load influence and d.
Seasonal temperature changes and other influences: design a unified forced centering equipment and aiming mark. e.
Based on the results of the drawing design and site selection, write a technical design book for precision engineering horizontal control measurement. 4.7 The design drawing of the horizontal control network, the type of mark and the level of measurement accuracy of the precision engineering horizontal control measurement technical design book. a.
Overview of the survey area and the evaluation and utilization of the existing horizontal control network measurement data, the measurement benchmark and measurement standards adopted.
Measurement mark structure, forced centering equipment, pier mark specifications and burial requirements. c
The significance of the accuracy requirements proposed by the project. Technical design plan and expected accuracy estimation. f
The instruments, equipment, observation methods, instrument calibration locations and cycles, and new technology applications. .
Operation implementation plan and schedule,
5 Precision engineering height control network
5.1 The main function of the precision engineering height control network is to provide accurate data of height control points for precision engineering construction, equipment installation, adjustment and completion measurement, a.
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Provide a unified elevation control basis for the phased and layered construction of different groups of unconstructible (structure) buildings and the same building (structure) in the same project.
5.2 Design principles of precision engineering elevation control network5.2.1 The layout scope of the elevation control network should be compatible with the horizontal control network.5.2.2 The accuracy of the elevation control network should ensure that the error of the key parts relative to the design size during the engineering construction meets the requirements.5.2.3 The elevation control network uses the error in the height difference of the measuring station as the basis for accuracy design and classification. The level of the elevation control network generally does not have the meaning of the upper network controlling the lower network. A higher network can be laid in a lower network. At this time, only one point is selected as the elevation starting point of the higher network. If the project requires, it is also allowed to lay the project control network in succession. 5.2.4 The elevation control network should be a node network composed of closed or attached routes. Branch lines shall not be laid. The circumference of the closed loop and the length between nodes shall be determined according to the needs of the project construction.
5.2.5 The route slope in the elevation control network should be gentle and the field of vision should be wide. The line of sight should be more than 10 meters away from the surrounding obstacles. 0.5m. 1. On the first-level elevation route, instrument piers or movable instrument platforms should be installed. The deviation between adjacent reference points shall not exceed 0.5m. 5.2.6 The control points of the engineering control network should be located in stable and reliable places that can be continuously measured and preserved for a long time. They should avoid underground pipelines, oil wells, gas wells, water wells, ground fissures, landslides, vibration cracks and other places that are easy to cause damage. Large precision engineering projects should have elevation benchmarks. 5.2.7 The elevation control points set up by the sky should be built after a rainy season. In frozen areas, they should also be built after a thaw season. Period. Elevation control points buried in rock formations or indoors should be observed at least half a month later. 5.3 Levels of precision engineering elevation control networks
The elevation control network uses the mean error of the height difference of the measuring station as the accuracy index and is divided into levels 2, 1, and 4 (see Table 2). Table 2
Mean error of the height difference of the measuring station
Gauge line length
Elevation measurement - Mean error of the height difference of the measuring station M is calculated based on the network layout. a.
When the number of closed loops exceeds 20, connect (1) or let it be calculated
M =+ Y/m/N
Formula: one-loop total, mm;
calculate the number of stations corresponding to each value;
N—number of closed loops
When the number of closed loops is less than 20 and the number of measuring sections in the network exceeds 20, use formula (5) to calculate: M-± VLaat/n_4A
the round-trip discrepancy value of the measuring section, nm;
n——the number of measuring stations corresponding to the calculation;
N: the number of round-trip discrepancy values,
When the number of daily average values of deformation observations of independent measuring stations exceeds 20, use formula (6) to calculate. c
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M -- - V[/2(N - 1)
[ = E(X,+1 - X,)
Formula: X, -- average value of observed height difference in the ith month, nimt3 continuous difference of average values of adjacent days, mm;
number of average values,
if the deformation is too large, the deformation effect should be removed: perform accuracy statistics. 5.4 Data to be collected before technical design of precision engineering height control network a. Topographic map and traffic map of the project area at a scale, geological, earthquake, meteorological, and hydrological data, 6)
b. Overall planning map, layout map, construction map, construction schedule and related technical documents of engineering construction. In particular, it is necessary to clarify the accuracy requirements for height measurement and confirm them with technical documents. r. Elevation control survey data of the project area, including leveling route map, point record, result table, gravity measurement data, technical summary, etc.
5.5 Technical design procedure of precision engineering project control network The main points and lines of the engineering building (structure) are displayed on the general construction plan. If it is a multi-story structure project, it should be displayed in layers. a
bDraw the existing horizontal control points and elevation control points (including newly designed horizontal control points) on the map. C. According to the needs of engineering construction and the requirements of elevation control points, select elevation control points on the map so that the elevation control points are evenly distributed around the building (structure). According to the requirements of the observation route, connect the relevant control points (including appropriate horizontal control points) to form an elevation control network. d: On the designed elevation control network, use analytical methods (equal weight substitution method, parameter method or other methods) to calculate the height difference between certain fixed points in key parts or the weighted number of the project (hereinafter referred to as the measurement object), calculate the mean error of the height difference of the measuring station according to formula (7), and select the level of the project control network by comparing with Table 2.
4 = 4/(3 Q)
Where: M is the mean error of the survey station of the proposed height control network: AF... The error of the survey object F:
Q is the weighted inverse of the survey object F (the error rate of the height difference of the survey station is used as the unit weighted mean error).
e. By increasing or reducing the redundant observation method, a variety of schemes are designed, and the scheme that is suitable for the survey area conditions and instrument performance and can meet the accuracy requirements of the project is selected to lay out the height control network. T. Determine the point location and mark type on the spot
Write the precision engineering height control measurement design book, g
5.6 Precision engineering height control measurement technology design book Contents a.
Design drawing of elevation control network. Type of sign and level of measurement accuracy. Overview of survey area and evaluation and utilization of existing commercial control survey data. b.
Elevation system and measurement standard adopted. Determined elevation starting point and detection plan. d.
Classification table of survey signs to be set up.
Basis for determining the level of accuracy of elevation control network, estimation of elevation accuracy of certain specific points in key parts required by engineering construction. Instruments, equipment, observation methods and instrument metrological calibration locations and periods adopted. Operation implementation time and schedule.
6 Construction of survey signs
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6.1.1 Various marks for precision surveying are the basic basis for various precision surveying. According to their uses, they can be divided into plane point marks, high point marks and flat high point marks.
6.1.2 Before burying the marks, the relevant engineering geology, hydrogeology and meteorological data in the project area should be carefully studied. According to the pressure-bearing performance of the foundation, the depth of the constant temperature layer, the depth of frozen soil, the depth and fluctuation amplitude of the groundwater level, and the total load after the completion of the building, the pressure per unit area and the dynamic load information during the operation of the building, the buried depth of the marks should be determined. 6.1.3 The types and specifications of various marks should be determined according to the observation purpose and the geological conditions in the project area. The buried marks should be stable and durable to ensure the convenience of short-term and long-term use. External decoration should also consider coordination with the appearance of the corresponding building and be beautiful in shape: 6.1.4 The depth of the ground anchor of the precision measurement control point should follow the following principles: a. The ground anchor of the plane point and the elevation point should be buried below the soil compression depth and close to the constant temperature zone; b. If the constant temperature zone is located above the lower line or edge line of the compression depth, then the depth of the ground anchor buried at the elevation point should be the edge line of the soil compression depth:
. When selecting the depth of the buried anchor, the soil water level and its seasonal changes must also be taken into account. So that the control point ground anchor is buried outside the range of water level changes.
6.1.5 Before and after the construction of the sign, a detailed sign list should be compiled. The type and specifications of the signs used should be stated on the list: and the burial map should be drawn. The burial map includes the point plan, the sign cross-section, and the point geological profile. 6.2 Plane point markings
6.2.1 Plane point markings include depth markings, observation and aiming marks, etc. 6.2.2 The semi-surface reference point markings of precision engineering surveys shall adopt depth markings. According to the needs and possibilities of the specific project, depth markings can be selected from inverted hammer-type pipes, light transmission markings or rigid bracket markings, etc. The specifications of depth markings are shown in Appendix A. 6.2.3 The construction of depth markings shall meet the following requirements: a. The anchor of the mark shall be firmly fixed in a stable rock formation, and the mark body shall be isolated from the buildings and the upper layers of the ground. b. The center of the anchor shall be able to be strictly transmitted to the working water surface in a straight line, and the verticality of the borehole shall not be less than 17200.
6.2.4: Observation markings shall be constructed for plane control points of all levels. Observation markings shall be constructed with materials such as concrete, granite, quartz and steel pipes. See Appendix B for mark specifications.
6.2.5 When burying observation marks, the bottom of the pit should be filled with sand first, and then compacted or poured with a concrete base. After the mark is firmly buried, the top of the net fence should be compacted to prevent the mark from tilting or shifting. 6.2.6 The plane point mark should be equipped with a forced centering device. The centering error of the forced centering device should be determined according to the measurement accuracy, generally ±0.025~±0.1mm
6.2.7 Aiming marks can be selected according to the specific situation, such as screw-in pole mark aiming marks, heavy balance ball aiming marks, direct insertion brand marks and embedded aiming marks: the specifications of various marks are shown in the appendix (.6.2.8 Aiming marks should meet the requirements of large contrast of the map, symmetrical pattern, obvious geometric center or axis, small phase difference and no deformation.
6.3 Elevation point mark
6.3.1 The mark of the high point includes deep buried metal pipe mark, rock layer mark, shallow buried metal pipe mark , concrete marks, wall work marks, foundation marks and marks on equipment, etc.
6.3.2 The elevation reference point marks for precision elevation measurement generally adopt deep buried marks. According to the needs and possibilities of the specific project, deep buried marks can be selected from deep buried bimetallic wire marks, deep buried bimetallic pipe marks and deep buried steel pipe marks. The specifications of deep buried marks are shown in Appendix D.
6.3.3 The construction of deep buried marks shall meet the following requirements:. The selection of the location for the buried deep marks must take into account the geological structure of the area. The deep buried marks should be buried outside the pressure propagation range of the building:
:comGB/T 15314—94
c: The buried depth inside the building should be greater than the depth of the seventh compression layer of the foundation. 6.3.4 The marks of each level of elevation control points are generally rock formation marks, buried steel pipe marks or concrete level marks. The specifications of the above various marks are shown in Appendix E
6.3.5 When burying rock formation marks, the rock foundation trench must be cleaned and the concrete with a weight ratio of water, cement, sand and gravel of 0.6:1.24 must be poured to make the mark and the stem trench a whole. 6.3.6 When burying shallow buried steel pipe marks, the bottom of the drill hole must be compacted and the metal pipe should be inserted 30cm below the bottom of the manhole. 6.3.7 When burying concrete level marks, it must be poured on site with reinforced concrete. 6.3.8 When installing and adjusting large equipment components and observing vertical displacement, various elevation marks should be set on the equipment components or buildings. The type of elevation mark can be selected from wall marks, foundation marks or set Prepare the mark. The specifications of the above various marks are shown in Appendix F. 6.3.9 When setting up the wall mark and the foundation mark, the vertical ruler part must be processed into a hemispherical shape or have obvious protruding points, and it must be coated with rust-proof agent. The buried mark should be firm and stable, and should be erected at the same time as the scale. 6.4 Level and high point marks
6.4.1 The marks of the level and high point include deep buried marks, observation marks and aiming marks. 6.4.2 The specifications of the deep buried level and high point are shown in Appendix G. The observation marks and aiming marks should meet the requirements of horizontal measurement and elevation measurement. 6.4.3 The buried method of the level and high point mark can refer to the relevant provisions in 6.2 and 6.3. 6.5 Submission of materials
After the construction of the survey mark is completed, the following materials should be submitted: the record of the survey mark point and the mark structure diagram, the foundation section diagram of the buried point: a
The entrusted custody book of the survey mark:
C. Technical summary. Acceptance report.
7 Precision Angle Measurement
7.1 General Provisions
7.1.1 Precision angle measurement is the main link in precision triangulation, precision angle measurement, precision traverse measurement and precision orientation measurement. The angle measurement error of each level of precision angle measurement calculated by triangle closed error should not exceed the provisions of Table 3. Table 3
Angle Measurement Error
7.1.2 Angle measurement should be carried out in a favorable observation time when the target image is clear and stable. The first-level angle measurement should be carried out in a controlled environment. The distance between the gauge line and the surrounding obstacles should be more than 0.5m. 7.1.3 During the observation process, attention should be paid to always keep the level bubble of the sighting part centered. The level deviation value should be recorded for each sighting direction to correct the horizontal angle and vertical axis tilt. The instrument must be re-leveled before measuring. 7.1.4 The rotation of the instrument should be smooth and balanced. When aiming at the target, it should rotate in the specified direction. 7.1.5 A forced centering device should be used at the instrument station and the target sighting point. 7.1.6 In order to eliminate or reduce the influence of the long and short period errors of the optical theodolite's scale division, the micrometer scale error and the line error, or to eliminate or reduce the influence of the electronic theodolite's scale division error, when using an optical theodolite, the horizontal angle observations should be evenly distributed at different positions of the scale and micrometer; when using an electronic theodolite, the horizontal angle observations should be evenly distributed at different positions of the scale. For this purpose, an observation scale table must be compiled in advance. 7.2 Types and inspection items of precision angle measuring instruments 7.2.1 The instruments that can be used for precision angle measurement are DJ07, DJ1, DJ2 optical theodolites and Jingyao electronic theodolites. It can also be based on specific 1 process
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7.2.2 For optical theodolites that have just left the factory or are newly received (without inspection data), first check the integrity and performance of the various components of the instrument, adjust the blue axis relationship of the instrument, and then inspect according to the following items: Inspection of the optical performance of the telescope!
Inspection of the correctness of the operation of the focusing mirror:
Inspection of the correct rotation of the sighting part;
Inspection of the eccentricity of the sighting part
Inspection of the error of the horizontal scale scale division;
Inspection of the eccentricity of the horizontal scale;
Determination of the scale value of the sighting part level:
Inspection of the source dynamic difference of the optical micrometer
Determination of the line error of the optical micrometer:
Inspection of the correctness of the use of the vertical passive screw, determination of the error of the coincidence of the radial scale lines of the optical micrometer of the horizontal scale; inspection of the systematic error caused by the displacement of the instrument base when the sighting part rotates! Inspection of the error of the optical micrometer division,
Determination of the difference between the horizontal axis and the vertical axis n
According to the corresponding level of observation method, number of measurements and limit requirements, test a horizontal angle result in more than four directions. 0.
7.2.3 The inspection and measurement methods of optical theodolites shall be carried out in accordance with the relevant appendix of the "National Specifications for Blue Angle Measurement and Precision Traverse Measurement". 7.2.4 Before the start of each precision angle measurement task, the precision optical theodolite shall be inspected for items a, b, h, ij, lm, h in 7.2.2. Items d, f, and m in 7.2.2 are generally measured once every two to three years. Item e in 7.2.2 is only inspected once after leaving the factory. 7.2.5 For newly purchased precision electronic theodolites, the integrity and efficiency of all parts of the instrument should be checked first, and then the following items should be inspected:
Inspection of the optical performance of the telescope;
Inspection of the accuracy of the operation of the focusing mirror;
Inspection of the correct rotation of the aiming part;
Inspection of the eccentricity of the aiming part;
Inspection of the eccentricity of the horizontal disk;
Measurement of the angle value of the level of the aiming part;
Inspection of the accuracy of the vertical micro-motion screw; Inspection of the stability of the instrument base when the aiming part rotates; # Determination of the difference between the horizontal axis and the vertical axis; j.
Determination of the error in the zeroing key;
Determination of the diameter error of the horizontal disk!
Determination of electronic subdivision;
-Determination of errors in direction observation:
According to the observation method, number of measurements and tolerance requirements of the corresponding level, test a set of horizontal angle results in four or more directions. 7.2.6 Before the start of each precision angle measurement task, the precision electronic theodolite should be inspected for each item u, b, g, h, i, jk in 7.2.6. The three items de and jk in 7.2.6 are generally measured once every two to one year. 7.3 Technical requirements for angle observation of horizontal control networks at all levels 7.3.1 Horizontal angle observation generally adopts the direction observation method. When the number of directions is not more than three, it can be omitted. If necessary, the full combination angle measurement method and other observation methods that can meet the accuracy requirements can also be used. If the angle measurement method cannot meet the accuracy requirements, the precision distance measurement method can also be used.The corresponding angle value is calculated by back-calculating the side length value.
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7.3.2 The operation procedure of the direction observation method is shown in Article 77 of the National Triangulation and Precision Traverse Measurement Specification. 7.3.3 When the total number of directions exceeds 6, the observation can be divided into two groups. Each group should include at least two common directions (one of which is the common zero direction), and the difference between the two groups of common direction angle values should not be greater than 2 times the error in the corresponding level of angle measurement. The final result of the group observation is adjusted according to the equal-weighted group observation.
7.3.4 The tolerance of the directional observation method should not exceed the provisions of Table 1. Table 4 Theodolite type Optical micrometer Curve Second re-reading Electric theodolite Two sighting readings difference Note: DJO5 is a theodolite with a horizontal error of no more than 20.5 in one round. Half survey Zeroing error Within one round 2C Mutual error Value in the same direction Mutual error of each round 7.3.5 The operation procedure of full combination angle measurement - one round shall be carried out in accordance with Article 76 of the National Triangulation and Precision Traverse Measurement Code. 7.3.6 The line error of the full combination angle measurement method shall not exceed the provisions of Table 5. Table 5
Type of theodolite
Mutual difference of the target readings
Mutual difference of the upper and lower half angle values
Technical requirements for horizontal angle observation of each level of angle measurement control network shall comply with the provisions of Table 6: Table 6
Number of double-direction measurement rounds
: -m. Number of measurement rounds
Directional weight of full combination angle measurement method F
7.3.8 Technical requirements for horizontal angle observation of each level of traverse shall comply with the provisions of Table 7 DJ2
Five differences of each single value at the same angle
The maximum closure error of the triangle
Note: The error is the number of measurement stations.
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7.3.9 Remeasurement and selection of horizontal angle observation results DJI
Azimuth angle error
Any result that exceeds the limit specified in this specification shall be remeasured. A complete round that is remeasured due to exceeding the limit is called a remeasurement. A round that is not completed due to a.
dish, wrong direction, reading error, touching the instrument, excessive bubble deviation and other reasons is not considered a remeasurement when it is re-observed. b. When the 2C five differences in a round exceed the limit or are converted to the same starting direction, the mutual differences of the same direction values in each round exceed the limit, the direction that exceeds the limit should be remeasured and the zero direction should be measured in parallel. When remeasurement is required due to the mutual difference of the round exceeding the limit, in principle, the rounds with the largest and smallest values in the observation results should be remeasured except for obvious isolated values.
If the 2C mutual difference in the zero direction exceeds the limit or the zeroing difference in the lower half of the measurement round exceeds the limit, the entire measurement round should be remeasured. 4. In a survey by the directional observation method, when the number of re-measured directions exceeds 1/3 of the total number of measured directions (including re-measurement of one direction among three directions), the survey should be re-measured.
e. When the directional observation method is used, the number of direction measurement rounds re-measured for each station's basic survey round should not exceed 1/3 of the total number of all direction measurement rounds, otherwise the entire station should be re-measured.
f. Calculation of the number of re-measurements by the directional observation method: In the observation results of the basic survey round, re-measurement of one direction is counted as one direction measurement round, and the whole survey round re-measured due to zero direction exceeding the limit is counted as (n-1) direction measurement rounds. The total number of all direction measurement rounds for each station is calculated as (-1)m, where n is the total number of directions at the station and m is the number of measurement rounds.
When the triangle closure error, polar conditions, baseline conditions, and azimuth conditions are exceeded and the free terms are re-measured, all results should be re-measured. 7.4 Precision Directional Measurement | |tt||Precision directional measurement can be carried out by astronomical azimuth measurement, precision gyro orientation and other methods. The operation requirements shall be carried out in accordance with the relevant specifications.
7.5 Submission of materials
After the precision angle and precision directional measurement work is completed, the following materials should be submitted: 8. Horizontal control network outline, point record or point description, technical design book! b.
Instrument inspection and constant measurement notebook;
Horizontal angle and azimuth observation notebook,
Horizontal angle observation record, azimuth calculation, field results verification data, e.
Technical summary, acceptance report.
8 Precision distance measurement
8.1 Level and basic accuracy regulations for precision distance measurement (see Table 8). Table 8
Mean error in side length and distance
GB/T 15314—94
8.2 The specific determination of the grade and accuracy of precision distance measurement should be based on the characteristics of precision engineering projects, accuracy indicators, the purpose and purpose of the horizontal control network, and other factors, and comprehensive analysis should be carried out in accordance with the provisions of Table 8. 8.3 Distance measuring instruments should be selected according to the engineering accuracy indicators. If necessary, the classic measurement means, methods and instruments and equipment can be improved according to the characteristics and accuracy requirements of the project, and special instruments and equipment that are compatible with the observation methods and accuracy requirements can be designed and developed. 8.4 The entire measurement system must be equipped with a precision standard socket to provide forced alignment of instruments and equipment. The shaft attenuation of the standard socket and the tolerance requirement of the plug-in shaft are generally less than 0.025mm. The crosshair engraving line thickness of the plug-in shaft aiming mark is less than 0.020mm. The center of the crosshair should be consistent with the center of the plug-in shaft, and the deviation should be less than 0. 020 mm. The reading device used for precision distance measurement adopts a reading microscope with a magnification of 10-20, and the scale value of the measuring instrument is,01 mm. The scale value of the micrometer should be measured before operation. When the actual value is not equal to the standard value, the reading should be corrected. The thermometer uses a ventilated mercury thermometer with a scale of 0.2 mm. 8.6 For projects with periodic linear measurements, the same instruments, equipment, and installation should be used in each cycle, and the same measuring instruments used for the calibration of the equipment should be used. 8.7 Instruments and equipment should be used and cared for carefully. Before operation, the instruments and equipment should be inspected and calibrated to ensure that they remain in good condition during the entire operation. Choose the most favorable time to make measurements to ensure that the observation data is accurate and reliable. 8.8 In precision distance measurement, the observation results should be sorted and checked in time, and calculations should be made after confirming that all the observation results meet the requirements of the specifications. 8.9 Methods for precision distance measurementbZxz.net
8.9.1 Measuring with a chiseled ruler
For the safety of precision equipment, the accuracy can reach 0.030~0.050mm. According to the requirements of the work positioning, a set of chiseled rulers of different lengths are configured. The distance between the wire of the chisel and the center line of the forced centering bushing of the chisel shall be strictly equal to the corresponding design distance. The width of the double wire of the chisel is 0.2mm, the error of the engraved line is not more than 0.002mm, and the diameter of the steel wire used is 0.2mm. During operation, the steel wire is tightened at the two end points corresponding to the design distance of the chisel, and the joint is placed at the point of the installation equipment. The equipment to be installed is moved. With the help of a reading microscope, the double wire of the chisel and the steel wire are overlapped. The steel wire is relocated and the deviation value is read by the reading microscope. When the deviation value is less than 0.05 mm, the center line is adjusted. 8.9.2 Distance measurement with rod ruler
8.9.2.1 The rod ruler used to measure the line segment from the reference point to the control point on the engineering equipment and the short distance in the control network should be made of invar alloy or right quartz glass material with extremely small expansion coefficient, and accurately processed into a rod ruler with one end scale or two end point scales. The scale value of the scale is 1mm, and the line thickness is 0.015~0.020mml. The position error of any scale line relative to the zero scale line shall not exceed 0.005 Ω. The other end of the end scale should be equipped with a forced centering yoke column, and the middle plate has a water leveler for leveling. 8.9.2.2 According to the length to be measured, design and make a rod ruler of corresponding length so that the length to be measured is an integer multiple of the rod ruler. For the first-level accuracy requirement of precision distance measurement, when measuring with a rod ruler within 2m, no more than two scale sections are required, and when measuring with a rod ruler of 2~4m, no more than two scale sections are required.
8.9.2.3 When measuring with a rod ruler, the side length to be measured should be set on the same elevation plane. The side length should be measured back and forth on the plate. 8.9.2.4 When measuring the height of a set triangle with a rod ruler, a special tensioning device should be configured, and a steel wire with a diameter of 0.2 mm should be used to calibrate the direction of the long side of the triangle. When the side length is within 30~50m, the airflow speed on the side of the wire should not exceed Q.1m/s, and the side length should not exceed 0.2m/s within 30m.
8.9.2.5 The rod ruler must be calibrated before and after measurement. The error in the ruler length calibration should not exceed 0.010mm, and the difference between the calibration values before and after measurement should not exceed 0.020mm.
8.9.2.6 When using a rod ruler with scales at both ends for precision measurement, mark the front and back, and the scale F..Use a reading microscope to aim four times and count four times (four different positions of the scale should be photographed and read once), and the temperature of the scale is read as one measurement, and two measurements are observed. When using a scale with a scale at one end for precision measurement: on the front mark and the scale, use a reading microscope to photograph four times and read four times, and the temperature of the scale is read as one measurement, and two measurements are observed. The forced centering axis column of the mark is rotated 180° between the measurement rounds. The distance of each scale segment is calculated by the following formula.
Ruler with scales at both ends:
GB/T 15314—94
5(h) (ar-b) (a --- bg) + + tRuler with scales at both ends:
S(h) = (ub) + s + t
Wherein: S(h)—
The corresponding readings of the microscope at the intersection of the crosshairs and on the scale on the front mark: The corresponding readings of the microscope at the intersection of the crosshairs and on the scale on the front mark: abe
8. 9. 2.7
The calibration length of the ruler scale:
Ruler temperature correction number.
Technical requirements for measuring distance with ruler (see Table 9)
Ruler type
Two gradual points are equipped with scale
End points are equipped with scale
Operating scale
-Measurement readings
Number of drinks
Number of measurement rounds
Forward and return
Measurement readings
Number interval
Temperature interval
Reading and sending
Temperature position
（8）
Return
Length difference
8.9.2.8 When the mutual difference between the readings of a measurement round exceeds the limit, re-measure the readings. After discarding the maximum and minimum values, if the measurement round exceeds the limit, re-observe the measurement round. When the mutual difference between the measurement rounds exceeds the limit, re-observe the second measurement round. If the difference between the measured lengths of the two-way distance measurement exceeds the limit, the cause should be analyzed and the error should be corrected. 8.9.2.9 Accuracy assessment: Use the difference between the two measurements to calculate the distance error m-+adJ/2n
in the formula (10) where d is the half-mean value of the two measurements. mm
d is the number of times.
8.9.3 Automatic distance meter (distinvar>distance-(10)
8.9.3.1 When using an automatic distance meter to accurately measure the distance, place special reference marks at both ends of the measured distance. The center of the mark must be a diameter of 30 mm column hole, and cut off the velvet ruler of the same length as the measured distance. 8.9.3.2 The structure of the measured point has sufficient rigidity and is absolutely stable to ensure that it will not cause deformation when subjected to a certain tensile force. 8.9.3.3 The calculation formula for the measured length
L=+++(-)+(-)+(+
Where: 2-instrument probe reading value;
L——Index wire ruler calibration length:
1——Operation temperature;
Calibration temperature:
8.9.3.4 Operating requirements for precision measurement of automatic distance meter a.
t)-(11 )
Automatic distance meter precision measurement, observe four rounds of measurement. Two rounds of measurement for each round trip, the instrument equipment and position are changed during the return measurement, and the number is four for each measurement.
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