含砂量对黏-砂混合土力学特性影响的试验研究及工程应用

Experimental study on effect of sand content on mechanical properties of clay sand mixed soil and engineering application

广东省汕尾市龟龄岛码头工程采用黏-砂混合土地基。不同含砂量不排水剪切试验结果表明:1)随着含砂量增加,分形维数加速递减;2)抗剪强度特性逐渐由硬化型过渡为软化型;3)分形维数2.709 3(含砂量50%)为黏-砂混合土力学性能明显变化的界限值,两侧力学特性表现出较大差异;4)内摩擦角增大、黏聚力减少。结合经验公式的地基承载力、实际取材等因素确定含砂量为30%~40%,并选取12个监测点进行复核。

The Guiling Island wharf project in Shanwei City,Guangdong Province adopts clay-sand mixed soil foundation.The results of the undrained shear tests with different sand contents show that:1)The fractal dimension of mixed soil decreases rapidly with the increase of sand content.2)The shear strength characteristics gradually change from hardening type to softening type.3)The fractal dimension of 2.709 3(sand content of 50%)is the limit value for the obvious change of mechanical properties of clay sand mixed soil,and the mechanical properties of two sides show great differences.4)The angle of internal friction increases and the cohesion decreases.Combined with the foundation bearing capacity of the empirical formula,the actual material and other factors to determine the sand content of 30%~40%.12 monitoring points are selected to review the results.