岩土工程勘察规范翻译.doc

Code for investigation of geotechnical engineering ( Edition 2009 )11. Laboratory Test11.1General provisions11.1.1 Indoor test item of nature of geotechnique and test method should be as per provisions in this section， specific operation and test instrument be according with the provisions in current state standard, Standard for Soil Test Method (GB/T 50123) and state standard, Standard for Test Method of Engineering Rock Mass ( GB/T 50266 ), Parameters in valuation of geotechnical Engineering may consistent results of in-situ test or result of prototype observation re-analysis comparing provisions that be modified. 11.1.2 Test items and test methods should be in accordance with project request and determined by character of rock and soil properties. It should concern about rock and soil stress field in-situ and stress history, new stress field and new boundary conditions caused by project activities, when it is necessary, make test conditions approach reality as far as possible; should pay attention to rock and soil heterogeneity, non-isotropy and non-continuity. And pay attention to the rock mass and soil mass in engineering behaviour different from rock and soil samples.11.1.3 Special test method statement be composed for special test items.11.1.4 Megascopic method and brief describing be made for rock and soil significant behaviour before making test specimens.11.2 Soil Physical Properties Test ( Routine physical index test )11.2.1 Classified index test and Physic index properties test should be done for various engineering such soil as follow: Sand soil: distribution of grain size, specific gravity, natural moisture content, natural density, maximum density and minimum density. Silt: distribution of grain size, limit of liquidity, limit of plasticity, specific gravity, natural moisture content, natural density, and organic content. Clayey soil: limit of liquidity, limit of plasticity, specific gravity, natural moisture content, natural density, and organic content.Note:1. Particle grading test may only carry out for sand soil if grade I grade II or grade III test unachieved. 2. It may not carry out organic content test if megascopic observation identifies no organic matter.11.2.2 The method for limit of liquidity test should be base on the request of classified valuation and in according with provisions in current state standard Standard for Soil Test Method (GB/T 50123) and noted clarify in test report. Specific gravity may determine by experience in the region where there is experience, if any. 11.2.3 Permeability test may carry out when seepage analysis be necessary, foundation dewater design request permeability parameter provided and so on. Constant head permeability test apply to sand soil and stone; variable head permeability test apply to silt and clayey soil. Coefficient of consolidation, coefficient of volume compressibility, assumed coefficient of permeability may determined by consolidation test for the soft soil with lower permeability to water. Numerical value of coefficient of soil permeability adopted should be determined follow by comparing with the result of water pumping test or the result of water injecting test.11.2.4 When quality control be necessary such earthwork as backfilling or reclaim engineering carried out. Compaction test should be done. Relationship between dry density and moisture content, maximum dry density and optimum moisture should be determined by test.11.3. Soil Compression - Consolidation Test11.3.1 Maximum consolidation pressure should more than sum of effective self weight pressure plus additional stress when settlement calculation determined by constrained modulus. Test result may clear up and show by e-p curve. Calculation of Coefficient of compression and constrained modulus should adopt on pressure scope which equals soil effective self pressure up to the sum of soil effective self pressure plus additional stress. Rebound test should carry out when consider influence of foundation pit excavated and reloading. The pressure forced should simulate actual condition of loading and unloading.11.3.2 Test result may make it in order as per e-lgp curve when settlement calculation by consideration of stress history, to determine pre-period consolidation pressure, to calculate compression index and rebound index. Maximum pressure forced should meet request for completing e-lgp curve. In order to take out rebound index, unloading rebound should be done one time after estimate pre-period consolidation pressure, and then, continue loading, up to finish the last grade of pressure which is predetermined.11.3.3 Part of soil test specimen should be taken at the pressure as sum of effective self-weight pressure plus additional pressure, when relationship analysis between settlement and lasting time is necessary, make consolidation log in details and calculate consolidation index.11.3.4 Taking a certain amount of soil specimen test for and determine coefficient of secondary consolidation to calculate relationship between secondary consolidation settlement and its lasting time for thick strata of highly compressed soft soil if request.11.3.5 Triaxial compression test may carry out in order to provide such parameter as nonlinear elasticity, elastic - plastic model if stress-strain analysis of soil be request, and test should accord with condition as follow:1.using 3 or more different fixed confining pressure, make specimen consolidation, and then add axial compressive force grade by grade up to ones failure; each confining pressure test may carry out13 rebound, tidy test results to form axial stress strain curve correspond with each fixed confining pressure;2. Equivalent pressure consolidation test with the confining pressure equals axial pressure, loading grade by grade, acquire confining pressure and volume strain relation curve.11.4 Soil Shear Strength Test11.4.1method of triaxial shear test should be determined by the conditions as follow:1. Unconsolidated-undrained (UU) triaxial test may use for saturated clayey soil when loading velocity faster; for saturated soft soil should be test done later and under the condition of self weight pressure and let pre-consolidation ready.2. Consolidated-undrained(CU) triaxial test may adopt for preloading foundation work, good condition of drainage foundations, the engineering with lower loading velocity, or faster loading velocity but ultra-consolidated soil for the engineering and when water level decrease in high speed, stability of soil slope checking computations needed; Consolidated-undrained pore water pressure test should be adopted when the shear strength index request providing.11.4.2 Method of direct shear test should base on type of loading, loading velocity, and determined by condition of dewater for foundation soil. Unconfined compressive strength test may use for clayey soil with angle of internal friction0,for the soil specimen grade I.11.4.3.Residual strength test should carry out for determining such shear strength as shear failure interface existed in landslide zone. Determining assume parameter, may make after comparing with result of field observation re-analysis.11.4.4 When there is special request in geotechnical valuation, K0 consolidated undrained test, K0 consolidated undrained pore water pressure test, specific stress ratio consolidated undrained test, plane strain compression test and plane strain tension test may carry out.11.5 Soil Dynamic Properties Test11.5.1Dynamic triaxial test, dynamic simple shear test, resonant column test may use when engineering design request test to determine soil dynamic properties. During test method and test instrument option, should pay attention to its scope of dynamic strain applying 11.5.2 Dynamic triaxial test and dynamic simple shear test can use for determine soil dynamic properties as follow:1. Dynamic elastic modulus, dynamic damping and ones relation with dynamic strain;2. Specific dynamic stress dynamic strain relationship of soil under cyclic periodical numbers. 3. Relationship between liquefy shear strength of saturated soil and dynamic stress cyclic periodical numbers.11.5.3 Resonant column test may use for determining dynamic modulus and dynamic damping ratio during small strain.11.6 Rock Test11.6.1option of rock composition and physical test items may base on engineering require as follow:1. Rock of mine identification;2. Particle density and rock block density test;3. Absorption rate test and saturated absorption rate test;4. Resistance to disintegrative test;5. Swelling test;6. Freeze thaw test.11.6.2 Uniaxial compressive test should determine strength in dry and saturated condition separately and provide limit compressive strength and softening index. Elastic modulus of rock and Poissons ratio be determined by uniaxial compressive deformation test. Test and determine parallel and perpendicul