水泥砾质土三轴试验研究

Experimental study of cemented gravelly soil by triaxial test

对某水泥砾质土进行了三轴固结排水剪切试验,研究在不同水泥掺入比下水泥砾质土应力-应变关系和强度特性。结果表明:随水泥掺入比的增加,水泥砾质土试样在不同围压下应力-应变关系曲线均表现出不同程度的软化和剪胀现象,尤其在低围压(200 kPa)和高水泥掺入比(8%)下,剪胀性比较明显;在相同水泥掺入比下,峰值强度1 3 f(σσ)随围压的增加近似呈线性增长;与不掺水泥砾质土相比,水泥砾质土的内摩擦角因掺入不同量的水泥而得到不同程度的提高,黏聚力c随水泥掺入比的增加呈增长趋势,且增幅显著;割线模量E1和E5 0均随围压和水泥掺入比的增加而增加。不同高度的心墙堆石坝三维有限元算例的计算结果表明:水泥砾质土作为心墙材料可以显著降低土石坝心墙沉降。

A number of conventional consolidated drained triaxial compression tests of cemented gravelly soil were performed;and the stress-strain relationships and strength behaviors of the soil were investigated at different cement mixing ratios.The test results show that as the cement mixing ratio increases,the stress-strain relationship of cemented gravelly soil exhibits various degrees of softening and dilatancy under different confining pressures;and especially under low confining pressure（200 kPa） and high cement mixing ratio（8%）,the dilatancy of soil is more evident.Under the same mixing ratio of cement,the peak strength is nearly linearly increasing with the increase of confining pressure.Compared with gravelly soil without cement,friction angle φ of cemented gravelly soil increases in different degrees due to the different amounts of cement mixed into the gravelly soil.Cohesion c of cemented gravelly soil shows a growing tendency with cement mixing ratio increasing;and the tendency is more remarkable for cohesion c.The secant moduli of and increase with the increase of confining pressure and cement mixing ratio.Three dimensional finite element analysis results indicate that using cemented gravelly soil as the core will greatly decrease the settlement of earth-rock dam.