Standard No.:	GB/T 50123-1999
English Name:	Standard for soil test method [2006 Version]
Chinese Name:	土工试验方法标准
Professional Classification:	GB    National Standard
Issued on:	1999-06-10
Implemented on:	1999-10-1
Status:	superseded
Superseded by:	GB/T 50123-2019 Standard for geotechnical testing method
Superseded on:	2019-10-1
Superseding:	GBJ 123-1988
Language:	English
File Format:	PDF
Price(USD):	185.0
Delivery:	via email in 1 business day

1 General Provisions 1.0.1 This standard is formulated with a view to measuring the soil basic engineering properties and unifying the test methods in order to provide reliable parameters for the engineering design and construction. 1.0.2 This standard is applicable to the basic engineering property tests of the foundation soil and filling soil of various projects such as the industrial and civil buildings, water conservancy and transportation projects. 1.0.3 This standard divides soil only into coarse-grained soil and fine-grained soil. The soil names shall be determined according to the current national standard "Standard for Soil Classification" GBJ 145. 1.0.4 The soil test data collation shall be based on the study of control sample (test measured data) to estimate the soil element features and their change laws in order to make the soil test results provide accurate and reliable soil indicators for the engineering design and construction. The analysis and collation of the test results shall be in accordance with those specified in Appendix A. 1.0.5 The instruments and equipments used in the soil tests shall be adopted according to the current national standard "Primary Parameters and General Technical Specifications for Geotechnical Apparatus" GB/T 15406 and they shall be verified and calibrated periodically according to the current relevant regulations. 1.0.6 Not only the requirements stipulated in this standard, but also those in the current compulsory national ones of the nation shall be complied with. 2 Terms and Symbols 2.1 Terms 2.1.1 Acidity and Alkalinity It is the negative log of hydrogen ion in the solution. 2.1.2 Calibration A group of operations are to determine the relation between the indication of the metrologic instrument or measuring system, or the value represented by the material measures and the corresponding measured given value under specified conditions. 2.1.3 Effective Stress Path It is the change path of the effective stress on a certain surface in the soil compression process. 2.1.4 Freezing Temperature It is the maximum frozen temperature of the soil pore water. 2.1.5 Load Meter It refers to the steel ring or load sensor used in the strength test. 2.1.6 Load Rate It is the ratio of a certain level load increment to the previous level total load. 2.1.7 Parallel Measure It refers to adopting more than two specimens for simultaneous test under identical conditions. 2.1.8 Parameters of Shear Strength They characterize the indicators of soil shear performance, including the cohesion and internal friction angle. 2.1.9 Pure Water It includes de-aerated water and ion-exchange water. 2.1.10 Soil Specimen It is the representative soil specimen used in the test. 2.1.11 Saturation Soil It is the soil specimen whose pore volume is completely filled with water. 2.1.12 Suspension It is the mixture of soil grains and water. 2.1.13 Test The technical operation aims to test one or more features of the given specimen according to the specified procedures. 2.1.14 Thermal Conductivity It is the indicator denoting the soil heat-transfer capability. 2.1.15 Thaw Compressibility Coefficient The relative compression deformation is generated under the unit pressure effect after the thaw of the frozen soil. 2.1.16 Thaw-settlement Coefficient The relative settlement is generated under the deadweight pressure effect during the thaw process of the frozen soil. 2.1.17 Unfrozen-water Content It is the ratio of the unfrozen water mass to the dry soil mass in the frozen soil at a certain negative temperature (%). 2.1.18 Verification The verification is to provide proof for affirming the specified requirements are met. 2.2 Symbols 2.2.1 Dimension and time A——is the specimen cross-section area D——is the mean diameter of the specimen d——is the soil grain diameter h——is the specimen height t——is the time V——is the specimen volume 2.2.2 Physical Indicators Cc——is the curvature coefficient Cu——is the uneven coefficient Dr——is the relative density e——is the void ratio Gs——is the soil grain specific gravity IL——is the liquidity index Ip——is the plasticity index Sr——is the saturation ratio w——is the water content wL——is the liquid limit wP——is the plastic limit wn——is the shrinkage limit ——is the specimen density 2.2.3 Mechanical Indicators Af——is the pore water pressure coefficient when the specimen is destroyed atc——is the thaw compressibility coefficient av——is the compressibility coefficient B——is the pore water pressure coefficient Cc——is the compression index Cs——is the swelling index Cv——is the consolidation coefficient CBR——is the California bearing ratio c——is the cohesion Ee——is the resilient modulus Es——is the compressibility modulus k——is the permeability coefficient m——is the specimen mass mv——is the volume compressibility p——is the unit pressure pc——is the pre-consolidation pressure Pe——is the expansibility Q——is the seepage quantity qu——is the unconfined compressive strength S——is the shear strength Sf——is the unit settlement Sr——is the soil residual strength St——is the sensitivity u——is the pore water pressure s——is the collapsibility coefficient e——is the no-load expansion ratio ef——is the free swelling ratio ep——is the load expansion ratio wt——is the lixiviation collapsibility coefficient zs——is the deadweight collapsibility coefficient a——is the axial strain ——is the coefficient of dynamic viscosity f——is the frozen-heave factor ——is the normal stress ——is the effective stress ——is the shear stress ——is the internal friction angle n——is the contraction coefficient 2.2.4 Thermal Indicators T——is the temperature ——is the thermal conductivity 2.2.5 Chemical Indexes Bb——is the molality Cb——is the concentration Mb——is the mole mass n——is the amount of substance Om——is the organic matter pH——is the acidity and alkalinity Vn——is the mole volume W——is the soluble salt content n——is the mass concentration 3 Specimen Preparation and Saturation 3.1 Specimen Preparation 3.1.1 This test method is applicable to undisturbed soil and disturbed soil whose grain diameter is less than 60mm. 3.1.2 According to the requirements of the mechanical test, the density allowable difference of the same group of undisturbed soil specimen is 0.03g/cm3, while that of the same group of the disturbed soil specimen shall not be larger than ±0.01g/cm3. And the water content allowable difference of the same group of specimen shall not be larger than ±1%. 3.1.3 The key instruments and equipments needed for the specimen preparation shall meet the following requirements: 1 Fine screen: pore diameter shall be either 0.5mm or 2mm. 2 Washing screen: pore diameter shall be 0.075mm. 3 Platform scale and scale: if weighing 10kg, then its minimum division value shall be 5g; if 5000g, then 1g; if 1000g, then 0.5g; if 500g, then 0.1g; and if 200g, then 0.01g. 4 Cutting ring: made of stainless steel materials, its inner diameter is 61.8mm and 79.8mm and height 20mm; or its inner diameter is 61.8mm and height 40mm. 5 Sample hitter: as is shown in Figure 3.1.3-1. 6 Sample pressurer: as is shown in Figure 3.1.3-2. 7 Air extractor: vacuum meter and vacuum cylinder shall be installed. 8 Others: including soil knife, fret saw, soil crusher, oven, moisture cylinder and sprinkler. 3.1.4 The specimen preparation of the undisturbed soil shall be in accordance with the following steps: 1 Place the specimen cylinder according to the marked up and down directions, strip the wax seal and adhesive tape, and then open the specimen can and take out the soil specimen. Inspect the soil specimen structures. If the soil specimen is determined to be disturbed or the soil mass doesn't comply with the provisions, then the soil specimen shall not be prepared for the mechanical test. Figure 3.1.3-1 Sample Hitter 1-holding ring; 2-leader; 3-driving hammer; 4-sample cylinder; 5-cutting ring; 6-base; 7-specimen (a) mono-direction (b) dual-direction Figure 3.1.3-2 Sample Pressurer 1-piston; 2-duct; 3-shroud ring; 4-cutting ring; 5-pull rod; 6-specimen 1-upper piston; 2-upper duct; 3-cutting ring; 4-lower duct; 5-lower piston; 6-specimen; 7-pin 2 according to the test requirement, a thin layer of vaseline shall be coated on the inner walls of the cutting ring when cutting the specimen. The cutting edge shall be placed on the soil specimen down and be depressed vertically, and at the same time, the soil knife shall be used to cut the soil specimen along the outer side of the cutting ring until the soil specimen is higher than the cutting ring. Then the fret saw or soil knife shall be adopted to level off the soil specimen at the ends of cutting ring according to the soft and hard of the specimen. Last, scrub the outer walls of the cutting ring and weigh the total mass of the cutting ring and the soil. 3 Take representative specimen from the remaining soil to measure the water content. The sampling of such tests as specific gravity, grading analysis, and limit water content shall meet the requirements of Item 2 in Article 3.1.5. 4 As for the specimen cutting, the levels, scent, color, inclusions, cracks and uniformity of the soil specimen shall be described. And as for the soft soil which is inductile and supersensitive, it shall not be disturbed when prepared. 3.1.5 The specimen preparation of the disturbed soil shall be in accordance with the following steps: 1 Take the soil specimen out from the specimen cans or packaging bags and describe the color, scent, inclusions, soil types and uniformity of the soil specimen. And then cut the soil specimen into pieces and mix them uniformly. Last, take representative specimen and measure the water content. 2 As for those soil specimens which are homogeneous and have organic matters, representative specimen shall be adopted in natural water content state for the grading analysis and margin water content test. As for the heterogeneous soil, adequate soil specimen shall be adopted according to the test and kept in a ventilated place until they are dried enough to be crushed. As for the soil specimen of the sandy soil and those for specific gravity test, they should be dried at a temperature range of 105-110℃. As for those soils whose organic content exceeds 5% and those having gypsum and sulfate, they shall be dried at a temperature range of 65-70℃. 3 Put the air-dried or oven-dried soil specimen on a sheet rubber and crush them using a piece of wood. As for the soil specimen without sands and gravels, the tilth rotor may be used for crushing (the tilth rotor shall not destroy the integrity of the soil grain). 4 As for the dispersed coarse-grained soil and fine-grained soil, they shall be screened in accordance with those specified in Table B.0.1. As for the gravelly soil with the fine-grained soil, they shall be immerged by water and mixed fully to separate the coarse-grained soil and fine-grained soil. And then they shall be screened according to different test requirements. 3.1.6 The specimen preparation of the disturbed soil shall be in accordance with the following steps: 1 The specimen quantity shall be determined according to the tests and there shall be one or two spare test specimens. 2 Screen the crushed air-dried soil specimen by using a 2mm or 5mm-pore diameter screen. Take adequate soil specimen for test use below the screen and mix them uniformly, and then measure the air-dry water content. Last, fill them in a moisture cylinder or plastic bag for standby. 3 according to the needed soil quantity and water content, the water addition needed for specimen preparation shall be calculated according to the following formula: (3.1.6-1) Where, mw——is the water addition required for specimen preparation (g); m0——is the mass of the wet soil (or the air-dried soil) (g); w0——is the water content of the wet soil (or the air-dried soil) (%); w1——is the water content required for the specimen preparation (%). 4 Weigh the screened air-dried soil specimen and spread them flat in an enamel tray. Spray water uniformly on them, mix them fully and put them into a soil container and make the lid close. Moisten the soil for a day and night; the wetting time of the sandy soil may be discretionally reduced. 5 Measure the water content of the wetting soil specimen at different places (at least for two places). The water content difference shall meet the requirements of Article 3.1.2. 6 according to the cutting ring volume and needed dry density, the wet soil needed for preparation shall be calculated according to the following formula: （3.1.6-2） Where, d——is the dry density of the specimen (g/cm3); V——is the specimen volume (cutting ring volume) (cm3). 7 The hit method and pressure method may be adopted for the preparation of the disturbed soil. 1) Hit method: pour the wet soil required according to the cutting ring volume and the dry density into a sample hitter with cutting rings and then compact them to the required density. 2) Pressure method: pour the wet soil required according to the cutting ring volume and the dry density into a sample pressurer with cutting rings and then compact them to the required density by the static pressure passing the piston. 8 Take out the cutting ring with specimen and weigh the total mass of the cutting ring and specimen. As for those specimens which needn't saturating and testing immediately, they shall be stored in a humidor for standby. 3.2 Specimen Saturation 3.2.1 The following method should be adopted respectively for the specimen saturation according to the permeability performances of the soil specimen: 1 As for the coarse-grained soil, the soaking saturation method shall be adopted. 2 As for the fine-grained soil whose permeability coefficient is larger than 10-4cm/s, the capillary saturation method shall be adopted. While for those fine-grained soil whose permeability coefficient is less than or equal to 10 - 4cm/s, the pumping saturation method shall be adopted. 3.2.2 The capillary saturation method shall be in accordance with the following steps: 1 Apply frame saturator (see Figure 3.2.4-1b), put filter paper and porous plates on the upper and lower surfaces of the specimen, put them into the saturator and fasten the nut. 2 Put the finished saturator into a water tank and add some water (the specimen should not be submerged by the water). Close the tank cap. The soaking time shall not be less than two days and nights so that the specimen can be fully saturated. 3 Take out the saturator, loosen the nut and take out the cutting ring. Dry the outer walls and weigh the total mass of the cutting ring and the specimen. And last calculate the saturation ratio of the specimen. If the saturation ratio is lower than 95%, then the specimen shall be saturated further. 3.2.3 The saturation ratio of the specimen shall be calculated according to the following formula: (3.2.3-1) Or (3.2.3-2) Where, Sr——is the saturation ratio of the specimen (%); Wsr——is the water content of the specimen after saturated (%); sr——is the density of the specimen after saturated (g/cm3); Gs——is the soil grain specific gravity; e——is the void ratio of the specimen. 3.2.4 The pumping saturation method shall be in accordance with the following steps: 1 Adopt stack or frame saturator (see Figure 3.2.4-1) and vacuum saturation device (see Figure 3.2.4-2). Place the porous plate, filter paper, cutting ring with specimen, filter paper and porous plate in the median of the lower plate of the stack saturator in turn. And according to such an order, overlap them to the pull rod height bottom-up. Cover the upper plate well and screw down the nut in the upper end of the pull rod. Clamp all the cutting rings between the upper and lower plates. 2 Put the saturator with specimen into a vacuum cylinder. Coat a thin layer of vaseline between the vacuum cylinder and the lid, and then make the lid close. Connect the vacuum cylinder with the air pump and trigger the air pump. When the vacuum manometer reading is near to an atmospheric pressure value (the pumping time shall not be less than 1h), open the pipe clip and let the water gradually fill in the vacuum cylinder. And during this process, the vacuum manometer reading should remain constant. (a) Stack saturator (b) frame saturator Figure 3.2.4-1 Saturator 1-plate; 2-porous plate; 3-cutting ring; 4-pull rod Figure 3.2.4-2 Vacuum Saturation Device 1-saturator; 2-vacuum cylinder; 3-rubber stopper; 4-two-way valve; 5-exhaust valve; 6-pipe clip; 7-diversion pipe; 8-water container; 9-air pump 3 Stop pumping after the saturator is submerged. Open the pipe clip to let the air enter the vacuum cylinder. Keep it still for a period of time, which should be 10h for the fine-grained soil so that the specimen can be fully saturated. 4 Open the vacuum cylinder and take out the specimen with the cutting ring from the saturator. Weigh the total mass of the cutting ring and the specimen and calculate the saturation ratio according to formula (3.2.3). If the saturation ratio is lower than 95%, then the specimen shall be pumped and saturated further.

1 General Provisions 2 Terms and Symbols 2.1 Terms 2.2 Symbols 3 Specimen Preparation and Saturation 3.1 Specimen Preparation 3.2 Specimen Saturation 4 Water Content Tests 5 Density Test 5.1 Core Cutter Method 5.2 Wax Sealing Method 5.3 Irrigation Method 5.4 Sand Replacement Method 6 Soil Grain Specific Gravity Test 6.1 General Rules 6.2 Pycnometer Method 6.3 Suspending Weigh Method 6.4 Siphon Cylinder Method 7 Grain Analysis Test 7.1 Sieve Analysis Method 7.2 Densimeter Method 7.3 Pipette Method 8 Limit Water Content Test 8.1 Liquid-plastic Limit Combined Mensuration 8.2 Dishing Liquid Limit Test 8.3 Rolling and Scrubbing Plastic Limit Test 8.4 Shrinkage Dish Method-Shrinkage Limit Test 9 Relative Density Test of Sand 9.1 General Rules 9.2 Minimum Dry Density Test of Sand 9.3 Maximum Dry Density Test of Sand 10 Compaction Test 11 CBR test 12 Resilient Modulus Test 12.1 Lever Pressiometer Method 12.2 Strength Tester Method 13 Permeability test 13.1 General requirement 13.2 Constant head permeability test 13.3 Variable head permeability test 14 Consolidation test 14.1 Standard consolidation test 14.2 The continual loading test of strain control 15 Loess collapsibility test 15.1 General rules 15.2 Collapsibility coefficient test 15.3 Deadweight Collapsibility coefficient test 15.4 Leaching deformation coefficient test 15.5 Collapsibility initial pressure test 16 Triaxial compression test 16.1 General requirement 16.2 Instrument and equipment 16.3 Specimens preparation and saturation 16.4 Unconsolidated undrained triaxial test 16.5 consolidated undrained triaxial test 16.6 Consolidated drained triaxial test 16.7 Multilevel loading test of one specimen 17 Unconfined compressive strength test 18 Direct shear test 18.1 Slow-shear test 18.2 Consolidated quick shear test 18.3 quick shear test 18.4 Direct shear test of sandy soil 19 Strength test of repeating direct shearing 20 Free Swell Test 21 Swelling Test 21.1 Linear Swelling Test 21.2 Non-linear Swelling Test 22 Swelling Force Test 23 Shrinkage Test 24 Density-Test of Frozen Soil 24.1 General Requirements 24.2 Suspending Weigh Method 24.3 Joint Determination Method 24.4 Cutting Ring Method 24.5 Sand-filling Method 25 Frozen Temperature Test 26 Test of unfrozen-water content 27 Thermal Conductivity Test of Frozen Soil 28 Frost Heaving Capacity Test 29 Thaw Compression Test of Frozen Soil 29.1 General Requirements 29.2 Indoor Thaw Compression Test of the Frozen Soil 29.3 Thaw Compression Test 30 Acidity/Alkalinity Test 31 Soluble Salt Test 31.1 Preparation of Lixivium 31.2 Determination of Total soluble salt 31.3 Determination of Carbonate and Bicarbonate 31.4 Determination of Chloride 31.5 Determination of Sulfate- EDTA Complexation Capability Method 31.6 Determination of Sulfate-Turbidimetric Method 31.7 Determination of the calcium ion 31.8 Determination of magnesium ion 31.9 Atom-Absorption Spectrometry of Calcium Ion and Magnesium Ion 31.10 Determination of Sodium Ion and Potassium Ion 32 Medium Dissolved Salt (gypsum) Test 33 Insoluble Salt (calcium carbonate) Test 34 Organic Matter Test 35 Centrifuge Moisture Equivalent Test of Soil Appendix A Test Data Collation and Test Report Appendix B Requirements and Management of Soil Specimen Appendix C General Requirements of Indoor Soil Instruments Appendix D Test Record of Various Items