以广东省韶关市某中小河流治理工程的清滩土石料为研究对象,开展室内大型三轴剪切试验和大型直剪试验,研究不同试验方法下清滩土石料的抗剪强度特性。大型三轴剪切试验结果表明,清滩土石料强度随着应变的增加逐渐增加,无明显峰值强度,为弱硬化型,同时抗剪强度随着围压的增大而增大,体应变呈剪缩型变化;大型直剪试验结果表明,土石混合料在不同垂直压力下均具有一定的峰值强度,呈现微弱的应变软化特性;不同试验方法确定的清滩土石料抗剪强度参数对比结果为,大型三轴剪切试验所得到的抗剪强度参数最大,大型常规直剪试验次之,大型叠环式剪切试验最小。研究成果表明,清滩土石料具有较好的抗剪强度,防渗处理好后可作为较好的筑堤材料。

The shear strength characteristics of earth-rock material from river dredging obtained from different test methods are examined via large-scale indoor triaxial shear test and direct shear test. The earth-rock material from river dredging in the harnessing project of a small and medium-sized river in Shaoguan, Guangdong Province is taken as a case study. The results of large-scale triaxial shear test show that the shear strength of the earth-rock material from river dredging increases with the rising of strain and confining pressure, displaying weak hardening with no obvious peak strength. The results of large-scale direct shear test show that peak strength of the earth-rock material from river dredging exists under different vertical pressures, characterized by a weak strain softening. Comparison of shear strength parameters among different test methods implies that the shear strength parameters obtained from large-scale triaxial shear test is the largest, followed by those of conventional direct shear test and piled ring shear test in sequence. The research results prove that the earth-rock material from river dredging is of good shear strength, hence can be used as good embankment material after anti-seepage treatment.