In order to reasonably design the foundation of buildings on frozen soil, ensure the safety and normal use of buildings, and achieve advanced technology and economic rationality, this specification is formulated. This specification is applicable to the design of industrial and civil building foundations in seasonal frozen soil and perennial frozen soil areas. JGJ 118-1998 Design Specification for Building Foundations in Frozen Soil Areas JGJ118-1998 Standard Download Decompression Password: www.bzxz.net

Industry Standard of the People's Republic of China
Code for Design of Foundations of Buildings in Frozen Soil AreasJGJ 115 --96
Editor: Heilongjiang Kangdi Architectural Research InstituteDepartment: Ministry of Construction of the People's Republic of China#Effective DateApril 1, 1999
Notice on the Issuance of the Industry Standard "Code for Design of Foundations of Buildings in Frozen Soil Areas"
Construction Standard [1998] No. 224
According to the requirements of the Ministry of Construction's "Notice on Issuing the Plan for the Formulation and Revision of Professional Standards and Specifications for Engineering Construction in 1989 (_89] Construction Standard No. 8), the Code for Design of Foundations of Buildings in Frozen Soil Areas compiled by Heilongjiang Kangdi Architectural Research Institute has been reviewed and approved as a mandatory industry standard with the number JiJ11895, which will be implemented on April 1, 1999.
This standard is managed by the China Academy of Building Research, a building engineering standard and technical unit of the Ministry of Construction, and is specifically interpreted by the Heilongjiang Cold Region Building Science Research Institute. This standard is organized by the Standardization Institute of the Ministry of Construction and published by the China Building Industry Press.
Ministry of Construction of the People's Republic of China
November 13, 199
1 General provisions
2 Technical symbols
2.1 Terms
2.2 Symbols
3 Soil classification and investigation requirements
Soil names and classifications
3.2 Requirements for investigation of permafrost foundations
4 General provisions for the design of permafrost foundations
4.2 Design for frozen state
Design for gradually thawing state...
4.4 Design for pre-thawing state
4.5 Design for foundation containing ice layer, saline thawed soil and frozen peat soil
5 Depth of foundation
Seasonal foundation
5.2 Perennial frozen soil foundation
Calculation of multi-year special soil foundation
6.1 —General provisions..
6.2 Calculation of ground in frozen state
6.3 Calculation of ground sources in gradual melting state and pre-melted state
13—4
13—4
13—6
13—7
13—7
13—9
13—10
13—10
13 -10
13—11
13—11
13—12
13-:12
13—14
13—15
General provisions
Ventilated foundation on permafrost 1:
7.3 Thermal foundation:
Thermal piles, thermal foundation
Slope and retaining wall
8.1 Slope
8.2 Retaining wall
Appendix A
Record set R
Design values ​​of frozen soil strength index
Melting of ground salt in buildings in permafrost
....E.
Stability of foundation due to frost heave||t t||[.1 Foundations of continuous buildings
B.2 Foundations of heating buildings
C.3 Paved foundations
Appendix D Calculation of characteristic values ​​of frozen ground temperature and the highest ground temperature under the thawing plate
.1 Calculation of characteristic values ​​of frozen ground temperature
E.2 High temperature of frozen ground under the thawing plate Appendix F Determination of ventilation hole area of ​​overhead ventilation foundation Appendix F
Static load test of frozen foundation for many years
Design value of freezing-thawing settlement coefficient and shrinkage index
Appendix
Vertical static load of single pile on multiple frozen foundations
13—2
13--18
13—18
13—18
: 13—18
13—19
13—22
.... 13-22
:13—23
13—26
13 29
[3—31
13 31
：13—34
13—36
[3---37
13—37
13—37
13—40
13—40
13—42
Appendix" Calculation of hot pile and hot rod foundation
Appendix K Frozen: Calculation of thermal physical indexes not with soil (value)
Appendix L Explanation of terms used in this specification
Additional explanation
Explanation of clauses
13—43
13 --45
13—49
13—50
13—50
1. 0. 1 In order to reasonably design the foundation of buildings on soil foundations, ensure the safety and normal use of buildings, and ensure advanced technology and economic rationality, this code is formulated. 1.0.2 This code is applicable to the design of industrial and civil building foundations in seasonal and perennial frozen areas. 1.0.3 The design of foundations in frozen areas shall meet the requirements of the current national standard "Code for Design of Building Foundations" GBJ7. 1.0.4 When designing the foundation of buildings on frozen foundations, in addition to complying with this code, it shall also comply with the requirements of the current national standards and specifications. 2 Terms and symbols 2.1 Terms 2.1.1 Tangential frost heave forces Tangential frost heave forces The force acting on the side surface of the foundation in the tangential direction when the foundation soil is swelled. 2.1.2 Normal frost-heave forces
normal frost-heaveforecs
When the soil expands during freezing. Force acting on the bottom of the foundation in the normal direction. 2.1.3 Horizontal frost-heafarces When the soil expands during freezing, the force acting on the structure or foundation surface in the horizontal direction, including the action in the tangential and normal directions. 2.1.4 Freezing strenkth Shear strength of frozen soils Shear strength of frozen soils The strength of frozen soils to resist shear stress.
2.1.6 Fractured ground (soil. rock) Containing ice: (if).
2.t.7 Perennially frozen ground, pernafrost Soil (rock) whose freezing state lasts for two years or more. 2.Ig Seasonally frozen ground: the ground surface layer that is frozen in winter and completely thawed in summer (regular): 2.I.9 Saline frizen soil: when the content of free salt in frozen ground exceeds the specified limit, it is called saline soil; 2.1.10 Frozen peat soil: when the degree of peatification in old soil exceeds the specified limit, it is called frozen peat soil; 2.1.11 Carnectel frozen ground: the multi-year gravel soil directly below the thawing layer; 2.1.12 Non-permafrost detarchment n frnzen ground: the multi-year frozen ground with a freezing depth shallower than the upper limit; 2.1.13 Massive cryostructure: the structure on the frozen ground where there is no large ice body visible to the naked eye. 2. 1.14 Layerert cryostructuta Structure in which ice in the soil is distributed in layers. 2.lIs Reticulatrd eryastruciure Structure in which ice bodies of different sizes, shapes and directions form a roughly continuous grid.
2. 1. t6 Ice layer5
Thin layer of ice in the soil with layered and reticulated structures. 2. I. 17 Ice inclusion In addition to acid ice, underground ice bodies such as porous ice, ice layers, and ice bodies. bZxz.net
2. 1.18 Unfrozen-warer contentUnder certain negative conditions, the ratio of the unfrozen-warer content to the lower and upper warer content in the soil. 2.1.19 Initiation temperature The freezing temperature of the ten corresponding to the initial water content. 2.1.20 Characteristic value of frozen ground temperature The sum of the annual average ground temperature, annual variation depth of ground temperature, annual average increase of ground temperature below the bottom of the active layer, annual maximum ground temperature and annual minimum ground temperature. 2.1.21 Annual anpliude of temperatur: Annual variation of ground temperature Half the difference between the highest and lowest ground temperature values ​​at a point on the surface or in the ground in a year. 2.1.22 Mean annual ground temperature Mean annual ground temperature Mean annual ground temperature 2.1.23 Soil water content (frozen + total water content) Water content in frozen soil The ratio of the total mass of ice and unfrozen water in frozen soil to the mass of soil skeleton, expressed as a percentage. 2.1.24 Relative ice content Relative ice content The ratio of the mass of ice in frozen soil to the mass of all water. 2.1-25 Freezing front Freezing front The plane (curved surface) at the freezing temperature of the freezing front at the median ground level. 2.1.26 Thawed soil (rnek+ ground) The soil in this state of transition from the beginning of thawing to the consolidation stability under the existing stress.
2.1.27 Seasonal freezing layer
5 The surface layer that freezes in the cold season and melts in the warm season, and its annual average ground temperature is greater than 0, and its underlying layer is a non-frozen layer or non-permafrost. 2.1.28 Seasonal thawing layer (seasonal active layer) seasonally thawed layer The surface layer that freezes in the cold season and melts in the warm season, and its annual average ground temperature is less than the lower layer, and its underlying layer is a permafrost upper layer.
2.1. 29 Standard freezing depth standard thawing depth standard thawing depth The average value of the maximum frozen depth measured in 10 years in open areas outside cities with flat and dry surfaces. 2.1.30 Standard thawing depth standard thawing depth The average value of the maximum thawing depth measured in 1 year in open areas outside cities with flat and dry surfaces. 2.1.31 The burial depth of a permafrost layer under the condition of a natural permafrost table. 2.1.32 The burial depth of a permafrost layer under the condition of an artificial permafrost table. 2.1.33 Depth of zero annus lamplitude of ground temperature The depth of ground temperature below ground level that is relatively constant in a year. 2.1.34 Rhaw slumping The phenomenon that when the underground ice layer distributed on the natural slope melts due to heat, the overlying soil slides along the slope surface.
2.1.35 Freezing index
The algebraic sum of the products of the temperature below 0℃ and its corresponding duration in a year. 2.1.36 Thawing index
The algebraic sum of the products of the temperature above 0℃ and its corresponding duration in a year. 2.1.37 Open system (freezing): A system in which the water in the lower part of the frozen layer continuously migrates to the frozen surface during the freezing process. 2.1.3x Closed system (freezing): A system in which no external water is added to the soil during the freezing process. 2.1.39 Ventilation modulus of natural ventilation foundation: The ratio of the total area of ​​the air inlet and exhaust holes in the ventilation space to the area covered by the outer ring of the floor plane.
2.1.40 Thermal pile (heat pipe pile)
Thermal pile (pile with a heat pipe) is a foundation with a standard steam two-phase fast convection circulation thermosiphon (gravity low-temperature heat pipe) device.
2. 1. 41 Heat exhaust foundation
Thermal probe foundariein
A system in which a gravity low-yield pipe is inserted into the foundation or placed on the receiving side. 2. 1. 42 Thaw buib under heated building Under a heated building, part of the perennial frozen ground soil undergoes melting, shaped like a plate or basin, and is called a melting plate.
2. 2. 1 Action and effect
Horizontal frost heave force;
Special heave force of the ground foundation:
Heat exhaust force of the building foundation:
Average additional force on the bottom of the foundation!
Additional forces on the freeze-thaw boundary;
Chordal frost heaving force:
"Frost heaving force on the frozen boundary
——Tangential frost heaving force
Frictional resistance in the unfrozen material, the drilling force in the frozen material and the reaction force on the extended foundation during the expansion,
Resistance and material properties
Moisture content on frozen material:
Moisture content at the beginning of thawing on frozen material;
——The final frozen water content Quantity;
bearing capacity on the top;
--freezing strength of the frozen soil and the base side surface;
--frozen soil shear strength;
--relative ice content of the frozen soil;
--the catalytic sinking coefficient of the frozen soil;
--the peat wall degree of the frozen soil,
--the expansion rate of the soil;
--the salinity of the frozen soil;
--the thousand density of the frozen soil: ||tt ||The density of the soil after thawing:
Frozen soil. Thermal resistance of the soil before melting,
Frozen soil. Thermal conductivity of unmelted soil,
-Frozen soil. Thermal capacity of the soil after melting:
Frozen soil: Thermal conductivity (thermal conductivity) of unmelted soil: dr, au-.
Annual average moisture content:
Temperature of the frozen soil at different depths along the pile.
2.2.3 Geometric parameters
2. Results Total area of ​​air holes in the foundation for air ventilation: 1. Maximum frost heave position:
2. Maximum melting depth of permafrost foundation for heating room: 1. Natural upper limit and artificial upper limit of permafrost. 2. Standard value and design value of seasonal freezing depth of soil; 3. Standard value and design value of seasonal melting depth of soil. 4. Minimum burial depth of foundation F
Thickness of old soil layer under the bottom of foundation.
2. 2.4 Calculation coefficients
Ventilation modulus of natural ventilation foundation;
- Stress coefficient on the frozen interface of double-layer foundation; -- Building plane shape coefficient:
7. -- Wind speed influence coefficient:
- Wind speed adjustment coefficient;
- Heating influence coefficient on the plane distribution of paint: -- The influence of slow mining on the freezing depth:
- Heating influence coefficient on the thickness of the base layer; -- The influence coefficient of freezing depth;
The influence coefficient of melting detection.
2. 2.5 Others
Q —Heat;
ETr, ZT.—
Freezing index and melting index:
m——meter, month.
3 Classification and exploration requirements of frozen soil
3.1 Name and classification of frozen soil
3.1.1 Frozen soil used as building foundation can be divided into seasonal frozen soil and multi-year old soil according to the duration; it can be divided into salt-induced frozen soil and frozen peat soil according to the different salts and organic matter contained; it can be divided into hard old soil, plastic frozen soil and loose frozen soil according to its deformation characteristics; it can be divided into several categories according to the thawing and heaving of frozen soil. 3.1.2 Salt flow frozen soil
3.1..1 The salt penetration degree of the salt filtration connection is 70% according to the following formula: the mass of easily soluble defects in the soil (g); the mass of the soil skeleton (g): 2 The strength index of salt evolution frozen soil should be taken according to the provisions of Appendix A Table A, (.2-2, Table 3.1-2.2
A.0.32. 3.1.2.3 The minimum limit value of salt debt on salt collapse frozen soil should be taken according to the provisions of Table 3.1.2. The amount of salt difficulty in thawing frozen soil is small and the soil is small. The loss (%>
3.1.3 Frozen peatification
age+
Table 3.1.2
The degree of carbonization of frozen mixed carbonization should be calculated according to the following formula: 3.1.3. 1
150 (%)
(3. 1. 3)
The mass of plant residues and peat in the above (g): 3.1.3.2 The strength index of frozen mud shall be taken according to the provisions of Appendix A Table A.0.23 and Table 73-7
A.0.3-3.
3.1.3.3 When the organic matter content does not exceed 15%, the degree of peatification of the frozen soil can be measured by potassium carbonate content, and when the organic matter content exceeds 15%, it can be determined by the loss on ignition method. 3.1.4 The compression coefficient of hard frozen soil should not be greater than n.01MPa, which can be approximated as the compression coefficient of non-compressible, plastic frozen soil. It should be less than 0.U1MPa, and the compression deformation should be taken into account. The total water content of coarse-grained soil shall not exceed 3% 3.1.5 The frost heave rate of the frozen upper layer can be divided into 15 categories: no frost heave, special frost heave, frost heave, strong frost heave and special frost heave, and should comply with the provisions of Table 3.1.5. The average frost heave rate of the frozen upper layer should be calculated according to the following formula: X100(%)
Surface frost heave (mm)r
Design depth (mm):
Thickness of the ground layer (nm).
Classification of frost heave of seasonal soil and seasonal thawing soil
The test results of the test results of the frozen upper layer are as follows: (i.e., frost heave)
Amine (neighboring ten
0. CT4n requires particle content of good
not more than) 1 group second (
center less than 0.074mm
comparison 0
medium shift (through
(. Center 1 4YmmL with light weight
too low 15%), fine (light
smaller than c.07lmm particle
in the amount of more than 10%2
Chen Shangda hot
technical limit
(3. 1. 5-1)
(3. 1. 5-2)
Table 3. 1. 5
water pull to remove the flat frozen peptide rate bed urea
fine surface Wang Xiao
run two hours (m)
not electric
i American leading
-1d- 5
source mouse American example
not Chen Zhang
not deep to
when the doctor sleeps
the name of the soil
frozen burning containing
water (
[-:1e-22
E—2ep-
w+5sgg-1 y
Wu\9eg
East knot period same place
Ping ditch Zhang Tai
down water property Chen ball
the effect of the surface is small
distance h. (m)
music exam job
not*product
ten exam single
3. 5-:ps5
original health inflammation group
not old version
special health
not bed swelling
special strong frozen non
original taste porridge
strong music photo
: limited water volume (%) large amount of speed film position
macro base language diagnosis 1. not in the table;
③ amount of world repellent large ten 2, cooling film reduced; $particle size U.05mm to light large F5% when not you account: 1 group of soil light filling material in the whole leather most 40 when its frozen nuclear war filling ten beauty judgment. 3.16 according to the soil melting sinking coefficient number. Permafrost can be divided into 15 categories: non-thawing settlement, independent thawing settlement, thawing settlement, strong thawing settlement and thawing settlement, and should comply with the provisions of Table 3.1.6: The flattening settlement coefficient of the frozen layer can be calculated as follows:
height × 100 ()
- the height of the old soil sample before thawing (mm) porosity ratio: , - the height of the frozen sample after thawing (mm) and porosity ratio. The thaw classification of permafrost
The public funds
The diameter is small
, :49: The impact includes
13%!
As (pebble) stone, taste,
middle school is less than
1. The total water content
12w 15
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ws ap i-
16: 2-24
++x+15
Net biomass layer
106:25
6,- 25
conc.3. 1. 6
Not sour flower ice
More frozen
Less ice under the sea
This melting tile
Figure ice depth
There is ice on:
The ice surface is ten
Not female courtyard
Less ice swimming.t
More ice association
Purple avoid sinking
Strong melting must
With socks source one
This melting resistance
Material brain courtyard
More ice glands "
Yiyuan Ze 1
Purple energy memory
Fear of freezing!
Little to have less ice bed soldiers
New melting ice institute
High freezing
Acid enzyme sinking, island ice paint 1
Note: The total technique water is the most v Calcium bed and point water; stop thawing soil, practice flow, circulation 1. High-pressure supplement soil is not in the list, 3.2 Frozen soil foundation investigation requirements || tt || containing + ice layer || tt || 3.2-" For seasonal soil and permafrost seasonal thawing layer, one original disturbed soil sample should be taken every 10mm along the depth direction to test whether it has natural water, plasticity, and limit; in the soil layer below the foundation depth, it should also provide "> viscosity, density, organic matter content: powder soil: density, particle size and organic matter content: sand: 1: particle density, take the maximum and minimum density, density, determine the foundation bearing capacity and assess the frost heave level 32.2 For permafrost main structure exploration sampling, transportation, and testing, measures should be taken to prevent the sample from melting.
3.2.3 The drilling depth for seasonally frozen soil foundations may be the same as that for non-frozen soil foundations; the drilling depth for annually frozen soil foundations shall not be less than 2 degrees below the foundation width for foundations designed to remain in a frozen state in accordance with Article 4.1.2, and shall be 3-5 degrees below the lower end of the foundation width for foundations designed to remain in a gradually thawing state or in a pre-thawing state in accordance with Article 4.1.2, and the relevant requirements for annually frozen soil foundations shall be met. 3.2.4 For permafrost foundations, according to the safety level specified in the current national standard "Design Code for Building Foundations BJ7", the quality requirements of frozen engineering and the ground temperature, the following design data should be selected: (1) Meteorological data: annual average temperature, climate change index (freezing index), monthly average wind speed in winter:
(2) Ground temperature data: annual average ground temperature, standard thawing depth (standard freezing depth), distribution of ground temperature along depth in late autumn and early winter;
[3 Physical parameters of frozen soil: dry density, total water content, relative humidity, salinity, Peatification degree, and frozen soil structure: (4) Thermophysical parameters of frozen soil and unfrozen soil: thermal conductivity, thermal conductivity, condensed heat capacity:
(5) Frozen soil strength index: structural strength, shear strength, bearing capacity: volume compression coefficient:
(6) Melting process and thawing process, melting settlement coefficient, thawing soil volume compression coefficient.
3.2.5 For the permafrost site where the safety level is - and important - buildings (the number of layers of the load-bearing structure and the cabinet structure exceeds? layers) is located, in-situ test and ground temperature observation should be carried out.
4 Design of permafrost foundation
4.1 General provisions
4.1.1 When designing buildings in areas with unknown permafrost distribution, permafrost should not be used as foundation.
4.1.2 When perennial soil is used as a building foundation, the design can be carried out in one of the following three states:
1 Perennial frozen soil is used as a foundation in a frozen state. In difficult-to-build conditions,During the construction and use of the building, the foundation should always remain in a frozen state. 1
2 The permafrost is used as the foundation in a gradually thawing state. During the construction and use of the building, the ground should be gradually thawed. 3 The permafrost is used as the foundation in a first thawed state. Before the construction of the building, the foundation should be thawed to the calculated depth or completely thawed. 4.1.3 The same design state must be adopted for each building; a unified design state should be followed for the same construction site.
4.1.4 The construction site should be equipped with drainage facilities, and the building's water dispersion slope should be made into an assembled type. For the foundation designed in a frozen state, the accumulation should be removed in time in winter, and the heating and water supply and drainage pipes should be insulated.
4.2 Design for maintaining frozen state
Design for maintaining frozen state is suitable for one of the following conditions: 1. The annual average ground temperature of permafrost is lower than 1.0; 2. The foundation soil within the bearing layer is in a hard frozen state; 3. Within the maximum thawing depth, there are thaw settlement, strong thaw settlement, and thaw subsidence foundations;
4. The foundation of buildings that are not overbuilt or have low yield and small floor area:
To maintain the frozen state of the foundation, the following foundation forms can be adopted. 4. 2. 2
1. Overhead ventilation foundation:
2. Fill in the gaps of ventilation pipes;
3. Raise the foundation with coarse granular soil;
4. Pile foundation, thermal insulation floor;
5 Insulated floor;
6 The bottom of the foundation extends to the calculated section below the human sleep depth: 7 Artificial refrigeration measures to reduce the upper temperature.
4.2.3 Design to keep the foundation soil frozen should adopt the approved silicon confirmation: For buildings with a safety level of Class 1 as specified in the current national standard or the Code for Design of Building Foundations 3GB] 7, thermal foundations can be used. Take measures to maintain the durability of pile body materials within the range of the joint melting layer.
4.2.4 During the construction and use of buildings, measures should be taken to prevent the surrounding environment from destroying the natural balance of temperature:
4.3 Design for gradual melting state
4.3.1 The design for gradual melting state should be applied to one of the following situations: 1. The annual average ground temperature of the site is 1.3~1.0°C; 2. The foundation within the bearing layer is in a state of frozen state; 3. The foundation is within the maximum melting depth range and has a small melting settlement or weak melting settlement; 4. The building is located in a relatively remote mountainous area, or the foundation has a thermal impact on the layer due to the heat carrier and the water supply and drainage system. 4.3.2 When designing for gradual melting state, one of the following measures should be adopted to reduce the deformation of the foundation:
4.3.2.1
4.3.2. 2
During the use of buildings, the melting depth of the ground should not be artificially increased: the foundation should be buried, or low-pressure soil should be selected as the bearing layer: 4.3.2.3 Insulated floors should be used. Overhead heat pipes and water supply and drainage systems: 4.3.2.4 Ground drainage systems should be set up
4.3. When the foundation 1 gradually melts and may produce abnormal deformation, the following measures should be taken:
43.3.1 Strengthen the integrity and rigidity of the structure. The plane of the building should be as simple as possible; additional settlement joints should be set up, and double reinforcement should be arranged at the settlement joints: reinforcement should be set up; tensioning bars should be set up at the vertical and horizontal joints; 4.3.3.2 Flexible structures that can adapt to uneven resistance should be used. 4.3.4 The maximum depth of gradual melting of the foundation under the building can be calculated according to the provisions of Appendix B of this code.
4.4 Pre-melting design
4.4.1 The pre-melting design is applicable to one of the following situations: 1. The annual average ground temperature of permafrost is not less than -0.5; 2. The foundation soil in the bearing capacity is in a plastic frozen state; 3. Within the maximum melting depth range, there are thaw settlements, strong thaw settlements and thaw subsidence soils and their interlayers with an unacceptable deformation; 1. The foundation of a building with a high air temperature and a small floor area. 4.4.2 When the deformation of the foundation within the melting depth designed according to the pre-melting state exceeds the allowable value of the building, one of the following measures can be taken: 1. Replace fine-grained soil with coarse-grained soil or pre-compress and densify 2. Keep the artificial upper limit of permafrost below the foundation surface the same; 3. If the foundation is buried,
4. Take structural measures if necessary to adapt to the deformation requirements 4.4.3 Design according to the short pre-melting state. When the frozen layer is completely melted, the ground should be designed according to the seasonal frozen ground.
4.5 Design of foundations containing thawed soil, salt-melted frozen soil and frozen peat soil
4.5.1 The upper ice layer should not be used as the foundation.
4.5.2 For the thawed soil foundation, when it is designed to be in a state of waiting for freezing, in addition to complying with the relevant provisions of Section 4.2, it shall also comply with the following provisions. 4.5.2.1 When pile foundation is adopted: the freezing strength of the interface between the drilled hole filled mud and the salt-melted soil shall be verified:
4.5.2.2 The unidirectional bearing capacity of a single pile shall be determined in accordance with the provisions of Article 7.3.5; 4.5.2.3 When the salt-melted soil is in a state of plastic freezing: the deformation calculation parameters of the foundation shall be determined by the in-situ static load test
4.5.2. When bored piles are filled with lime mortar or water-mixed mortar, the diameter of the drill column should be 100mm larger than the natural diameter. 4.5.3 When the foundation of salt-fluidized thawed soil is designed to be in a fully thawed or pre-thawed state, it should be carried out in accordance with the relevant provisions of Sections 4.3 and 4.4 and should comply with the relevant provisions of the current national standard GB7 for the design of building foundations. 4.5.4 When the foundation of peat-hardened soil is designed to remain in a frozen state, in addition to complying with the relevant provisions of Section 4.2, it should also comply with the following provisions: When the degree of agglomeration is not less than 25%, bored piles or inserted hot piles should be used: 4.5.4.1. 4.2 When drilling holes for piles, the freezing resistance of the interface between the mud and the old carbonized soil should be verified; when drilling holes for piles with lime mortar, the borehole diameter should be greater than the pile diameter by 100mm: the actual thickness of the sand cushion layer under the plate tip should not be less than 300mm; the actual thickness of the sand and gravel cushion layer at the bottom of the shallow foundation should be greater than 1/2 of the base width, and its bearing capacity should be determined according to the type of the original foundation soil. The foundation bearing capacity should be determined by the in-situ static load test. 4. 5.4.51
45.4.6 When the frozen peat soil is in a plastic frozen state, the calculation parameters of its foundation deformation should be determined by the in-situ static load test.
Deepness of foundation buried
5. 1 Seasonal frozen soil foundation
On the premise of meeting the foundation stability and deformation requirements, 5. 1. 1 For frozen foundation soil,
the stability of the foundation under the frost heave force shall be verified. 5. 1. 2 For frost heave foundation, the bottom surface of the foundation can be buried within the design frost heave range, and a certain thickness of bed soil layer (set burial depth to the maximum depth line) shall appear below the foundation surface, but the stability of the foundation under the action of frost heave force shall be verified in accordance with the provisions of the regulations. The stability verification of the foundation under the action of frost heave force includes the construction period, wintering process and the use period after construction.
The design depth shall be calculated using the following formula:
ZJ = Zapndwepm
Where 2. -Standard frozen depth. In the absence of local measured data, except for small areas, the national standard frozen depth line diagram of frost should be checked according to Figure 5.1.2: The influence coefficient of rock quality on frozen depth shall be adopted according to the provisions of Table 5.1.21 +
The influence coefficient of rock quality on frozen depth shall be adopted according to the provisions of Table 5.1.2-2;
The influence coefficient of surrounding environment on frozen depth shall be adopted according to the provisions of Table 5.1.2-3:
- The influence coefficient of terrain on frozen depth shall be adopted according to the provisions of Table 5.1.2-4. ep
5.1.3 When the ground is dug, there should be no frozen soil layer (including the one formed before the ground was dug and the one formed after the ground was dug); when the soil quality is relatively uniform, and the total settlement value of the foundation soil melting and compression is confirmed by calculation to be within the allowable range, or there is a frozen layer of a certain thickness determined by local experience.
: soil (rock)
clay soil
|fine acid, silt, silt
soil fat (liquidity) on the source of the system
soil quality (lithology)
medium, coarse, sand
drunk (pascal) rock
temperature (technical properties) on the bed depth of the system effect of ketone (bed nesting properties>
unexpected
period bed account
temperature conditions (aging properties)
special effects
correction: ①± the reading (your quality) effect of ketone·-item. The basic determination of anti-aging 3. 1.5,The impact of high environmental impact on the city is mainly due to the influence of the national environment, the soil, the environment, and the topography of the city. The main reasons are: ① The impact of high environmental impact, the following are used together, Yincheng, when the urban population is 20000 to 500000, according to the suburbs of the city, J3-12, East 5-1.2-5, Hao 9.1.2-2, 5.1.2-3, 5.1. 2-4
When the urban population is greater than 500,000 and less than or equal to 1 million, only the impact of the urban area is taken into account. Note: When the urban population is above 1 million, the impact of the urban area is taken into account, and the suburban area within 5km is considered. 5.1.4 Qualitative calculation of foundation When the relevant provisions of Record C are followed, and the design value of the frost heave force exceeds the standard value of the structure's deadweight (including the dislocation force in the foundation), the size and burial depth of the foundation should be readjusted. If this is not economical, the following measures can be taken to reduce or eliminate the frost heave force.
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