This specification is formulated to make the engineering construction in soft soil areas technologically advanced and economically reasonable and to ensure the safety and normal use of buildings. This specification is applicable to the engineering geological survey of building sites and foundations in soft soil areas. JGJ 83-1991 Engineering geological survey specification for soft soil areas JGJ83-1991 Standard download decompression password: www.bzxz.net

Industry Standard of the People's Republic of China
Silver Art Area
Soft Soil
Geological Survey Specification
JGJ83-91
Editor: China Academy of Building ResearchApproval Department: Ministry of Construction of the People's Republic of ChinaEffective Date: September 1, 1992
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Notice on the Release of Industry Standard "Soft Soil Area
Engineering Geological Survey Specification"
Construction Standard [1992] No. 79
To the Construction Committees (Construction Departments) of all provinces, autonomous regions, and municipalities directly under the Central Government, the Construction Committees of cities with independent planning status, and relevant departments of the State Council:
In accordance with the requirements of the former Ministry of Urban and Rural Construction and Environmental Protection Document (86) Chengkezi No. 263, the "Specifications for Engineering Geological Survey in Soft Soil Areas" compiled by the China Academy of Building Research has been reviewed and approved as an industry standard, numbered JGJ83--91, and will be implemented from 4-11-2
September 1, 1992.
This standard is managed by the Ministry of Construction's Comprehensive Survey Research Institute, the Ministry of Construction's survey and geotechnical engineering standards and technology management unit, interpreted by the China Academy of Building Research, and published by the Ministry of Construction's Standards and Norms Research Institute. Ministry of Construction of the People's Republic of China
February 20, 1992
Chapter 1
Chapter 2
Soft soil and its engineering geological characteristics 4-
Chapter 3
Section 2
Section 3
Section 4
Section 5
Chapter 4
Section 1
Section 2
Section 3
Section 4
Section 5
Chapter 5
Section 1
Section 2
Section 3
Chapter 6
Basic requirements for engineering geological survey
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General provisions
Feasibility study survey
Preliminary survey
Detailed survey
Construction survey
Investigation,
Exploration and testing
Engineering geological survey and mapping
Exploration and sampling
Indoor test
In-situ test
Engineering geological evaluation
Construction site conditions
Foundation bearing capacity and deformation
Foundation treatment
Groundwater and foundation construction
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Section 1? Groundwater Assessment
Section 2 Foundation Pit Survey
Section 3 Construction Dewatering
Chapter 7
Chapter 8
Appendix 2
Pile Foundation Engineering Survey
Site and Foundation in Strong Earthquake Areas
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|Sketch and Characteristics of Engineering Geological Zoning in Main Distribution Areas of Soft Soil in China
Basic Contents and Essentials of Survey Report
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Appendix III
Requirements for statistics of rock and soil physical and mechanical properties. …
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Appendix 4
Appendix 5
Appendix 6
Appendix 7
Selection of sample quality grade…4--11—14Empirical values ​​of relative density of soil particles and Poisson’s ratio
Empirical formula for vertical bearing capacity of single pile
Explanation of standard terms
Additional instructions
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Main symbols
Cross-sectional area of ​​pile body
-Compression coefficient
b—-Width of bottom surface of foundation
Cohesion of soil
C. -—, compression index on the surface
, elastic index on the surface
Cu, undrained shear strength on the surface
C. l: circumferential coefficient
-the burial depth of the box or the foundation
E. ——t deformation modulus
"large compression modulus
soil porosity
limit friction of the upper layer around the pile estimated by the relative penetration resistance of static penetration test
+liquidity index
-soil plasticity index
permeability coefficient
pile length
length of each pile section divided by the upper layer
empirical coefficient related to the depth of the compression layer
—self-weight pressure of the overlying soil layer
pre-consolidation pressure on the pile
-pH
P—average value of relative penetration resistance
average value of relative penetration resistance of static penetration test near the pile end standard value of bearing capacity on the pile end
standard value of friction around the pile
—unconfined compressive strength
Standard value of vertical bearing capacity of single pile
Settlement
——Soil saturation
Sensitivity
Length around pile
Water content of soil
Liquid limit of soil (measured by disc instrument)
Liquid limit of soil (measured by cone instrument)
Plastic limit of soil
Depth of exploration hole
——Reduction coefficient
Gravity density
Mass density
Looseness ratio of soil
Internal friction angle of soil
Chapter 1 General
Article 1.0.1 This specification is formulated to make the engineering construction in soft areas technologically advanced, economical and reasonable, and to ensure the safety and normal use of buildings. Article 1.0.2 This code is applicable to the engineering geological investigation of construction sites in soft soil areas. Article 1.0.3 is about the engineering geological investigation of soft soil areas. It is necessary to arrange the investigation work reasonably according to the characteristics of the project and soft soil, and correctly evaluate the engineering geological conditions of the construction site and foundation. For important buildings and soft soil foundations with special requirements, or sites that have an impact on the environment, monitoring should be carried out according to the needs of the engineering construction during construction and use. Article 1.0.4 In addition to implementing this code, the engineering geological investigation of soft soil areas shall also comply with the provisions of the relevant national standards currently in force. Chapter 2 Soft Soil and Its Engineering Geological Characteristics Article 2.0.1 The identification of soft soil shall meet the following requirements: Fine-grained soil with a gray appearance;
2. Natural water content is greater than or equal to the liquid limit; 3. Natural porosity is greater than or equal to 1.0. Article 2.0.2 The engineering properties of soft soil are compressibility, low strength, flexibility and low permeability. It is easy to collapse under the action of large earthquake forces.
Article 2.0.3 The soft soil layer has good stratification. In the interlayer, there are a few denser and coarser powder or sand layers, which become the variable soil layer in the soft upper layer.
Article 2.0.4 The main distribution area of ​​soft soil in Fujian can be divided into three areas according to engineering properties and natural geological and geographical environment, namely, along the Qinling Mountains to the east to the seashore north of Lianyungang, as the boundary of areas I and II, and along the Miaoling Mountains and Nanling Mountains to the east to the seashore of Diwang. As the boundary of areas II and II (Appendix I). This division can be used as a preliminary work for zoning, planning and exploration.
Chapter III Basic Requirements for Engineering Geological Survey Section 1-
General Provisions
Article 3.1.1 The survey stage can be divided into preliminary survey and detailed survey, and construction survey should be carried out when necessary. For large-scale factory sites and key projects, the survey should be divided into four stages: feasibility study survey, preliminary survey, detailed survey and construction survey; for projects with determined building properties and general plan positions, only detailed survey can be carried out. Article 3.1.2 The construction site shall be divided into a total of .The complexity of the project geology is divided into:
Simple site: flat terrain. Single geomorphic unit, no ponds or ditches, simple layers. Uniform soil quality, no adverse geological phenomena, no adverse effects of groundwater on the foundation.
Medium complex site: slightly undulating terrain, relatively simple ground ridges, fewer ponds and ditches, more complex layers. The soil quality changes greatly. The main bearing layer of the foundation has a large internal layer and base layer, and adverse geological phenomena are more developed. Groundwater may have adverse effects on the foundation.
Complex site: The terrain is relatively undulating. There are many single-center landforms, many city ditches, complex intersections, great changes in the quality of the land, large fluctuations in the hard and foundation surfaces of the main stress-bearing layers of the foundation, and the presence of liquefaction and earthquake subsidence. Groundwater has an adverse effect on the foundation transformation. When dividing the site, if there is a transition of categories, it is necessary to make a comprehensive analysis and formulation of the main direction. The engineering geological conditions of the construction site are complex. When there are obvious differences in the surface, the engineering geological zoning or segmentation should be carried out according to the differences in the stability, suitability and engineering geological conditions of the site, combined with factors such as topography, geological structure, adverse geological phenomena, soil properties and hydrogeological conditions. Article 3.1.4 The damage caused to the building by the foundation shall be divided into three safety levels according to the severity of its consequences, which shall meet the requirements of Table 3.1.4. Difficult-to-build grade
Safety grade; Consequences of destruction
Grade Very serious
Not serious
Table 3.1.4
Important buildings in construction projects of great significance to the national economy, commercial buildings with more than 14 floors
Single-story industrial plants with a permanent lifting capacity of 2300kN, buildings with strict restrictions on settlement
General buildings in construction projects of great significance to the national economy. Multi-storey residential buildings with 4 to 13 floors
Single-storey industrial plants with lifting elements <300kN, general industrial and civil buildings with certain settlement requirements
Residential buildings with 3 floors and below
Secondary buildings such as warehouses, various auxiliary workshops, etc. Article 3.1.5 The original records and data of investigation, mapping, exploration, testing, etc. at each stage of engineering geological investigation, as well as the collected relevant geological data, must be checked, sorted and verified on site in a timely manner before they can be used as the basic materials for the investigation results. The general content of the engineering geological investigation report and the requirements for data sorting shall be in accordance with the requirements of Appendix " and Appendix III. Article 3.1.6 After the exploration work is completed, the drilling should be done in time. Backfill.
Section 2
Feasibility Study and Exploration
Article 3.2.1 During the exploration phase of the feasibility study, an engineering geological evaluation shall be conducted on the stability and suitability of the proposed site as well as the technical and economic benefits: 1. Collect topographical, geomorphic, geological, hydrogeological, earthquake, frozen soil and engineering geological data of the proposed area and its vicinity, as well as local construction experience; 2. Conduct on-site investigation to understand the site's topography, strata, structure, soil quality, groundwater and adverse geological phenomena and other engineering geological conditions; 3. If the research and evaluation of the existing data does not meet the requirements for determining the construction site, an engineering geological survey or mapping shall be conducted as needed, and even necessary exploration work shall be carried out.
Article 3.2.2 Article 3. The feasibility study and investigation shall identify the unfavorable factors of the construction site:
1. Whether there are ancient river channels, dark ponds, hidden bays and valleys, and whether the foundation soil is seriously uneven;
2. Whether there are shallow bedrock with slopes or large fluctuations, and the risk of landslides should be analyzed;
3. Whether ground fissures, ground subsidence and liquefaction can occur during an earthquake;
4. Whether there are threats of floods and sea tides or adverse effects of groundwater;
5. Whether there are unmined mines and cultural relics underground. Section 3. Preliminary Investigation
Article 3.3.1 During the preliminary investigation stage, an evaluation shall be made on the stability of each building section on the site, and engineering geological data and basis shall be provided to determine the overall layout of the building, the foundation engineering plan of the main buildings, and the prevention and control of adverse geological phenomena.
Before the preliminary investigation, the following information shall be obtained:
Article
*, topographic map of the construction site; the scale should be 1:500~1:2000;
, obtain relevant geological data and construction experience, 3. The current status of underground pipelines within the site; 4. The nature, scale and preliminary ideas for the planning layout of the relevant projects, etc. Article 3.3.3 During the preliminary investigation stage, the following work should be carried out: 1. Preliminary investigation of the site's strata, genesis, bedding characteristics and physical and geometric properties, the distribution and thickness of the surface hard crust layer, and the burial conditions and undulations of the underlying hard layer and bedrock. Find a suitable bearing layer; ", preliminary investigation of the site The shape of the micro-topography, the distribution range and burial depth of the landfill;
3. Preliminary investigation of the hydrogeological conditions and freezing depth of the site; 4. Preliminary investigation of the distribution range of adverse geological phenomena on the site, such as ancient river channels, hidden bays, underground ditches, underground pits, etc., the impact on the stability of the site and their development trend;
5. For construction sites with an earthquake intensity of 7 degrees and above, the seismic effect of the site should be determined;
6. Preliminary investigation of the impact of environmental geology on the construction site; 7. When the load of the building is large, the possible foundation location or pile foundation plan should be evaluated.
Article 3.3.4 Preliminary surveys shall be conducted on the basis of collecting and analyzing existing data or on the basis of geological surveys and mapping. The arrangement of exploration points, lines and networks shall meet the following requirements:
1. The exploration line shall be perpendicular to the boundary line of geomorphic units and stratum boundary, and shall be perpendicular to the coastline at the seaside:
2. Exploration points shall be arranged according to the exploration line, and exploration points shall be arranged at the intersection of each geomorphic unit and geomorphic part. The exploration points shall be more densely arranged in areas with relatively large micro-geomorphic and stratum changes:
3. In areas with flat terrain, exploration points may be arranged according to a grid; 4. Exploration points and lines shall be arranged according to the idea of ​​planning buildings. Article 3.3.5 The spacing between exploration points in preliminary surveys shall meet the requirements of Table 3.3.5 according to the complexity of the site.
Spacing of exploration points in preliminary survey (m)
Site complexity
Simple site
Medium-complex site
Complex site
Article 3.3.6
Spacing of exploration points
150~200
100~150
50~100
The exploration holes for preliminary survey are divided into general and control types. Their depths are determined according to the possible building grades and exploration hole types, and should comply with the requirements of Table 3.3.6.
Preliminary exploration exploration hole depth (I)
Exploration hole types
Building management level
Level building
Level building
Level retreat building
General exploration hole
Note: Exploration includes drilling, in-situ tidal test and exploration well. 3.3.6
Excavation exploration hole
When encountering bedrock within the predetermined depth, except for some controlled exploration holes that should be drilled to an appropriate depth of bedrock, other exploration holes can reach bedrock. Controlled exploration holes generally account for 1/5 to 1/3 of the total number of exploration holes, and each landform unit should have a controlled exploration hole. Each major building area must have an excavation exploration hole.
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Article 3.3.7 During preliminary investigation, the exploration points for in-situ testing and sampling should be evenly distributed on the plane.
The vertical spacing of soil sampling and in-situ testing sites should be determined according to the characteristics of the stratum and the uniformity of the soil. Soil samples should be taken and in-situ tests should be conducted in each soil layer, and the number should not be less than 6 (groups).
During preliminary investigation, hydrogeological work should comply with the following requirements of Article 3.3.8:
The type of groundwater and the hydraulic connection with surface water, the conditions of recharge and discharge, and the range of change of groundwater level should be investigated; 2. If it is necessary to draw a groundwater level line map, the groundwater level should be uniformly observed, and representative water samples should be taken for erosion analysis. In general areas, the sampling
locations should not be less than 2, and more sampling should be taken in areas with pollution sources. Section 4 Detailed Investigation
Section 3.4.1 During the detailed investigation stage, an engineering geological evaluation of the building foundation shall be conducted, and geotechnical parameters, scheme demonstration and suggestions shall be provided for foundation design and foundation treatment.
Section 3.4.2 Before detailed investigation, the following information shall be collected: 1. General building plan with coordinates and terrain; 2. Preliminary site investigation report or nearby geological data; 3. Indoor and outdoor ground design standards of each building, status of superstructure and underground facilities, etc.
4. Possible foundation forms, sizes, burial depths, unit loads or total loads, allowable settlements and differential settlements, as well as foundation design and construction plans with special requirements.
Section 3.4.3. During the detailed investigation stage, the following work shall be carried out on the basis of the preliminary investigation; 1. Identify the stratum structure and its physical and mechanical properties within the building range, the consolidation history, strength and deformation characteristics of the soft soil, and evaluate the stability and bearing capacity of the foundation; 2. Identify the burial conditions, erosion and permeability of the groundwater; 3. Determine the possible changes and impacts of the foundation soil and groundwater during the construction (excavation, backfilling, piling, etc.) and use of the building, and propose prevention and control plans and suggestions; 4. Provide foundation deformation calculation parameters. If necessary, the foundation settlement, the settlement difference of adjacent foundations or the overall inclination of the foundation shall be calculated. Fifth, the parameters and support schemes required for calculating the stability of the slope after deep foundation excavation shall be provided, and the impact of foundation pit excavation and point precipitation on adjacent buildings shall be analyzed and evaluated. Article 3.4.4 The arrangement of exploration points for detailed investigation shall be determined by the complexity of the construction site and the grade of the building: First, for complex sites or first-class buildings, the arrangement shall be based on the main column line or the perimeter line of the building or the area with shape changes and stress concentration. For other sites and building grades, the arrangement shall be based on the perimeter of the building or the building complex. For major equipment foundations, the arrangement shall be separate. Third, Fourth, for complex sites, for individual structures with small area but heavy load or distant center of gravity (such as chimneys, water towers, etc.), the arrangement of exploration points shall not be less than 2. Article 3.4.5 The spacing of exploration points for detailed investigation. It shall comply with the provisions of Table 3.4.5:
Article 3.4.6 For the dark ponds and bays within the building area, the engineering nature and scope, depth, landfill time and materials used for filling shall be ascertained. Article 3.4.7 The depth of the exploration hole for detailed survey shall be determined according to the foundation calculation category:
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Site complexity
Simple site
Medium complex site
Complex site
Detailed survey exploration point distance (m)
"First-level building
Second-level building
Third-level building
50~ 76
1. For foundations calculated based on bearing capacity, the depth of the exploration hole should be determined based on the principle of controlling the strength of the main bearing layer of the foundation. When the length of the short side of the foundation is not more than 5m, the depth of the exploration hole is 4b for strip foundations and 2b for single column foundations. 2. For exploration holes that are used for deformation verification in addition to bearing capacity calculations, the depth should be 1~2m below the calculated thickness of the foundation compression layer or in accordance with the provisions of Table 3.4.7. When the site has a large area of ​​ground loading or a weaker underlying layer, the depth of the exploration hole should be deepened;
Detailed exploration hole depth (m )
Foundation form
Strip foundation
Single foundation research
Note: 1. The depth in the table does not take into account the influence of the adjacent foundation quotient, 2. The depth of the exploration hole is calculated from the bottom of the foundation. 3
Degree (m)
Table 3.4.7
Third, the depth of the controlling exploration hole of the box foundation and raft foundation should exceed the lower limit of the compression layer or be terminated when a hard soil layer is encountered within this range and there is no weak underlying layer below. The depth of the general exploration hole is based on the principle of controlling the main stress layer. The depth of the exploration hole can be calculated according to the formula (3.4.7): 2= d +mb
Where 2---- exploration hole depth (m);
d-the burial depth of a box foundation or a small foundation (m); the width of the bottom surface of the foundation (m), for circular or ring foundations, the maximum b --
Considering the large diameter,
The empirical coefficient related to the depth of the compression layer is 2.0 for the control hole and 1.0 for the general hole.
4. When there is a liquefiable soil layer in the exposed area, the depth of the exploration hole should not be less than 15m.
Article 3.4.8 During the detailed survey, the number of holes for taking soil samples and conducting in-situ tests should be determined according to the complexity of the site, the grade of the building and the area of ​​the site, and should not be less than 1/2 of the total number of exploration holes.
Article 3.4.9 During the detailed survey, the vertical spacing of the parts for taking soil samples and conducting in-situ tests should be determined according to the design requirements and the uniformity of the foundation soil. The length of the test is determined. Take one (group) of samples and obtain one (new) in-situ test data every 1~2.0m in the main stress-bearing layer of the foundation. The lower spacing can be appropriately relaxed. The number of samples and in-situ test data participating in the statistics for each soil layer in the same site should not be less than 6, and the load test data should not be less than 3. For interlayers or lenses with a thickness of less than 1m, it should be determined whether to take samples depending on the degree of influence on the foundation. However, in the main stress-bearing layer of the foundation, interlayers or lenses with a thickness of more than 50cm should take samples. Section 5 Construction Inspection
Article 3.5.1 Construction inspection should be carried out in the following circumstances. 1. After the foundation trench is excavated, the geological conditions are different and may affect the quality of the project:
2. Deep foundation construction design and construction require relevant foundation monitoring work,
, foundation treatment, reinforcement, design and inspection work are required 4. The location of buried ponds, banks, ditches, valleys, etc. needs to be further identified and processed,
5. When construction is expected, the stability of the soil slope needs to be monitored and processed. Investigation, exploration and testing
Chapter 4
Section 1 - Engineering Geology Investigation and mapping
Article 4.1.1 Contents of engineering geological investigation and mapping: During the feasibility study and investigation stage, the existing geological data should be investigated, collected, and studied, and on-site surveys should be conducted; during the preliminary investigation stage, investigations and engineering geological mapping should be conducted; during the detailed investigation stage, necessary detailed investigations and large-scale mapping should be conducted for certain engineering geological issues.
The results of the investigation and mapping should be used as the basis for preparing the investigation outline, arranging the investigation work, and as basic data for engineering geological evaluation. Article 4.1.2 The general contents of the case investigation and mapping should include: 1. The stratigraphic characteristics, genetic type, distribution range, burial conditions, stress history, etc. of the site;
2. The micro-geomorphological characteristics and adverse geological phenomena of the proposed site; Such as ancient river channels, hidden bays, foundation holes, wells, biological caves, underground pipelines, artificial fill, etc.,
3. Groundwater burial conditions, hydraulic connection between water level change amplitude and surface runoff and tides, recharge sources and groundwater quality types, etc. 4. Regional construction experience and experience in the development and utilization of soft soil foundations and underground spaces, as well as improvement and reinforcement.
5. Regional ground exposure intensity, earthquake damage and site effects. Section 4.1.3 The investigation and survey work should fully collect regional topographic maps, engineering geological maps, Ancient topographic maps or historical river maps (dark bay maps), etc.; fully collect the survey, design, construction and monitoring data of the existing buildings near the proposed site.
The scope of engineering geological investigation and mapping should include the related areas of the site other than those in Article 4.1.4
. The scale of the topographic map used for mapping can be 1:2000~1:5000 in the preliminary survey stage and 1:500~1:1000 in the detailed survey stage. For the geological boundaries of the building site, the mapping should be accurate. The error of the degree on the map should not exceed 3mm, and other sections should not exceed 5mm. Section 2 Exploration and Sampling
Article 4.2.1 Exploration work must select appropriate exploration methods based on the engineering characteristics and the engineering geological conditions and stratum properties of the site. In addition to drilling sampling, static penetration tests should be used for soft soils with large thickness or intercalated silty soils and sandy soils. Cross-plate shear tests should be used for other and fluid plastic viscosity. Article 4.2.2 Drilling shall meet the following requirements: ", "Use a fixed-core threaded lifter for rotary drilling When drilling, there should be drainage holes on the upper end of the soil lifter and drainage valves on the lower end to avoid vacuum shrinkage holes caused by drilling:
: During the drilling process, continuous construction is recommended to prevent shrinkage holes or holes. If it is difficult to form a hole or it is necessary to construct it temporarily, protective measures should be taken, such as casing protection, clean water wall protection, mud wall protection, etc. Fourth, the size must be accurately measured during drilling. The advance of soft soil should not be greater than 2in and the advance of powdery soil should not be greater than 1.5m. "Or it can be determined according to regional experience, but the stratification must be clear. The soil lifting rate should be greater than 80%. When there is a large amount of silty soil or sandy soil, which cannot meet the soil lifting rate requirements, a standard soil drill should be used to take soil samples for soil layer identification.
Article 4.2.3 Drilling records shall meet the following technical requirements: 1. Records shall be filled in the record form according to the drilling rounds and sections, and the sections shall be recorded separately. Several rounds shall not be combined and recorded later. 2. The measurement accuracy shall be ±0.05ms
3. In addition to general requirements, the contents of the records shall focus on describing the soft soil’s moisture, state, organic matter and humus content, odor, sand content (sand inclusion thickness), inclusions, structural characteristics, drilling difficulty, soil lifting conditions, etc. 4. For important boreholes, detailed sketches of soil sample structure or segmented photos of soil cores shall be taken, and soil core samples shall be preserved.
The quality of the soft soil sample and the soil sampler used, Article 4.2.4 Elements
Should be selected and determined according to the engineering requirements and the quality level of the required samples. And should meet the requirements of Appendix 4.
Section 4.2, 5 Series
Meet the following requirements:
When taking soil samples of grade I to II in the borehole, the operation should comply with the following requirements:
The thickness of the residual floating soil at the bottom of the hole shall not be greater than the length of the waste soil section at the upper end of the soil sampler. It is strictly forbidden to impact the bottom of the hole when lowering the soil sampler.
The static pressure method of the oil pressure feed device should be used to penetrate the soil sampler. When it is difficult to manually press the soil interlayer, a heavy hammer can be used to penetrate. When taking soil from deep layers, the hammer method can be used.
Article 4.2.6 The packaging, transportation and storage of soil samples shall meet the following requirements:
After the soil sampler is raised from the ground, the soil sample should be carefully lowered and properly sealed to prevent humidity changes. Soil samples should be placed upright, and it is strictly forbidden to place them upside down or flat, and they should be kept away from the sun or freezing.
2. Soil samples should be properly packed and filled with cushioning materials before transportation. During transportation, they should be kept stable to avoid bumping. For soil samples that are easily disturbed, tests should be carried out on site if conditions permit.
3. Soil samples should be stored at a temperature of 10-30°C. The storage time from the time of collection to the time of testing should not exceed 10 days. If necessary, they should be stored at a constant temperature and constant temperature, and the storage time can be appropriately extended.
4. If there is water separation or deformation after excavation, the quality grade of the soil sample should be reduced or the soil should be taken again.
Section 3 Internal Tests
Article 4.3.1 Indoor tests generally include soil physical property index tests, mechanical property index tests and chemical analysis. The actual test items should be determined comprehensively based on factors such as the nature of the project, foundation type, design requirements and soil characteristics to meet the needs of design and construction. The test methods, technical standards and instruments and equipment shall be implemented in accordance with the current geotechnical test method standard (GBJ123) and shall meet the requirements of this section.
Article 4.3.2 The relative density of soil particles shall be measured by the specific gravity bottle method for first-level buildings, and can be determined according to the local empirical value for second- and third-level buildings. It can also be adopted by referring to Appendix 5, Table 5.1.
Article 4.3.3 The liquid limit water content test shall adopt the cone instrument method. The disc instrument method can also be used when the project requires it. The relationship between the liquid limits measured by the two test methods shall be converted according to the empirical formula of each region. For soils that continue to sink over time after the cone is inserted into the soil and the plastic limit cannot be operated according to the requirements of the regulations, particle analysis shall be carried out and the name shall be determined by the particle composition.
Article 4.3.5 The permeability test of soil shall simultaneously measure the vertical and horizontal permeability coefficients of the soil. And it should be expressed in kn or k according to the overflow of groundwater. Provide data as 4-11-7
standard.
Chemical analysis of soil: The pH value, the content of chlorides, sulfates and carbonates should be mainly determined. Used to evaluate the corrosion to metals and concrete and their protection. The evaluation standards and protective measures can be implemented in accordance with the relevant provisions of the current geotechnical engineering investigation code. Article 4.3.7 is a conventional consolidation test. For the first-level building, the last level pressure can be selected according to the additional pressure of the building and the deadweight pressure of the soil. For the second and third-level buildings, the last level pressure should not exceed 400kPa. The compression coefficient α1- and compression modulus Es in the test report are values ​​corresponding to vertical pressures of 100 to 200kPa. When
a1-2≥0.5MPa\1, the compressibility is high, 0.1
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