膨胀土强度指标的试验研究及变异性分析

Experimental study and variability analysis of strength parameters of expansive soil

文章以合肥市某工程的重塑膨胀土为研究对象,进行了大量的快剪试验及固结快剪试验,研究了膨胀土的强度指标与含水率的关系,并对这些强度指标进行了数理统计,分析了强度指标的变异性。研究结果表明:随着含水率的增加,膨胀土的剪切破坏方式由脆性破坏逐渐过渡到塑性破坏;强度指标随着含水率的增加而减小,两者之间的关系可以用线性公式或指数公式表示;固结快剪试验的强度指标大于快剪试验的相应值。对于快剪试验及固结快剪试验,黏聚力的变异性大于内摩擦角的变异性,黏聚力和内摩擦角间的相关系数在多数情况下为负值;强度参数的变异性及参数间的相关系数越大,抗剪强度的变异性也越大。

Through a large number of quick direct shear tests and consolidated quick direct shear tests to the remolded expansive soil of a project in Hefei City,the relationship between water ratio and strength indexes of the expansive soil is studied.The mathematical statistics of these strength indexes is made and the variability of strength indexes is analyzed.The results of the study show that the way of shear failure of expansive soil is a gradual transition from brittle failure to ductile failure with the increase of water ratio;strength indexes of expansive soil decrease as water ratio increases,and the relationship between strength indexes and water ratio can be expressed by linear or exponential formula;strength indexes of consolidated quick direct shear tests are higher than those of quick direct shear tests.For quick direct shear tests and consolidated quick direct shear tests,the variability of cohesion is higher than that of internal friction angle,the correlation coefficient between cohesion and internal friction angle is negative in most cases.The higher the variability of strength parameters and the correlation coefficient of the parameters,the higher the variability of shearing strength.