粗粒土等压固结与K_0固结三轴试验比较

Comparison of Triaxial Tests with K_0-consolidated and Isotropically Consolidated Specimens of Coarse Grained Soil

对某堆石坝覆盖层砂卵砾石料进行了不同干密度试样中型三轴试验,试验包括常规各向等压固结的三轴排水剪试验(CID试验)和各向不等压(K0)固结的三轴排水剪试验(CK0D试验),对试验结果进行对比分析,研究2种试验方法对试验结果的影响。结果表明,2种试验所得到的应力—应变关系曲线总体规律比较一致,大小略有差异,CK0D试验的剪胀性比CID试验明显;不同围压下,2种试验的偏应力峰值差异(相对峰值)平均幅值为3.9%;对应3种密度(2.17、2.22、2.40g/cm3),CK0D试验各围压下的平均内摩擦角分别比CID试验的内摩擦角大0.88°、0.48°、0.43°;随着密度增大,2种试验的强度均显著增大,且强度指标随密度近似线性增大。列出并比较了2种试验的邓肯模型参数,两者没有显著的差异。

Using middle-scale shearing device,K0 consolidated-drained triaxial test and isotropically consolidated-drained triaxial test under different confining pressures are performed for three relative density overburden materials of a certain rockfill dam.Comparison and analysis are made to research the influence on the test results.The results show that total stress strain relationship regularities of the two tests are approximately identical.Yet there are some slight differences： The dilatancy of CK0D TEST is more obvious than CID TEST;Under different confining pressures,the difference between peak deviator stress（average amplitude） of the two tests is 3.9%;Average internal friction angles under various confining pressures in CK0D TEST are bigger than CID TEST.Corresponding to three differents densities（2.17,2.22,2.40 g/cm3）,the internal friction angles are 0.88,0.48,and 0.43 degree higher in CK0D TEST.As densities increase,the strengths of both two tests increase significantly.Moreover,strength indexes are nearly linearly increasing with the increase of density.Parameters of Duncan-Chang Model are given and compared.There is no statistics difference between the parameters obtained from the two tests.