不同堆置状态粗粒土剪切强度试验研究

Experimental Study on the Shear Strength of Coarse⁃Grained Soils in Different Heap Conditions

为研究不同堆置条件下排土场粗粒土的力学响应规律,开展了终排土体固结排水三轴压缩试验和在排土体快剪试验。研究结果表明,土体固结排水三轴压缩应力⁃应变曲线呈现先弹性后屈服再弱硬化的规律,体积⁃应变曲线有拐点,低围压时先剪缩后剪胀,高围压时以剪缩为主。在排土体快剪试验具有峰值强度,100~400 kPa时,峰值强度出现在剪切位移20%~30%之间,且剪应力⁃位移曲线呈弱化趋势;600~1200 kPa时,峰值强度出现在剪切位移30%~40%,随剪切位移增加,土体抗剪强度基本保持恒定或略有增大。不同堆置状态排土体抗剪强度参数取值各不相同。

A consolidated drained triaxial compression test and quick shear test of the final dumped soil were carried out in order to study the mechanical response of the coarse⁃grained soil in the dump site under different heap conditions.From the research,the stress⁃strain curve shows an initial elastic deformation,followed by yield deformation and weak hardening in the consolidated drained triaxial compression test,and an inflection point in the volume⁃strain curve shows that there are shear shrinks followed by shear dilation under low confining pressure,but shrinks dominates under high confining pressure.The quick shear test of the dumped soil shows there is peak strength.It appears 20%~30%of the shear displacement with the vertical loading of 100~400 kPa,showing a weakening trend in the shear stress⁃displacement curve.With the vertical loading of 600~1200 kPa,it appears 30%~40%of shear displacement,and the shear strength of the soil remains almost constant or in a slight increase with the increasing of shear displacement.The values of shear strength parameters for the dumped soil in different heap conditions are different.