论文部分内容阅读
利用一种新研制的土体扭转剪切渗透试验装置,研究黏土在压–剪耦合条件下渗透特性的变化规律。结果表明,当前固结压力与前期固结压力的相对大小决定着黏土剪切变形前后渗透系数和渗透稳定性的变化趋势。当固结压力大于试样的前期固结压力时,剪切面在剪切过程中发生压紧现象,没有产生明显的渗透弱面,试样总体渗透系数随着剪应变的发展略有减小。当固结压力小于试样的前期固结压力时,试样处于超固结状态,剪切面在剪切过程中逐渐发生剪胀破裂从而出现渗透弱面;在稳定渗流条件下渗透弱面具有自愈特性,但是自愈后的渗透系数显著增大。高固结压力下的正常固结试样剪切后的渗透稳定性没有显著变化。低固结压力下的超固结试样的渗透稳定性显著降低,其渗透破坏的形式为水头骤升条件下的水压楔劈效应将渗透弱面劈裂,进而产生裂缝冲刷破坏。
A newly developed soil torsional shear penetration test device was used to study the variation of clay permeability under pressure-shear coupling conditions. The results show that the relative sizes of the present consolidation pressure and the previous consolidation pressure determine the change tendency of the permeability coefficient and the permeability stability before and after clay shear deformation. When the consolidation pressure is greater than the pre-consolidation pressure of the specimen, the shearing surface compresses in the shearing process and does not produce obvious infiltration weakness. The overall permeability coefficient decreases slightly with the development of shear strain . When the consolidation pressure is less than the pre-consolidation pressure of the specimen, the specimen is in an overconsolidated state, and the shear surface gradually dilates and ruptures during the shearing process to appear the infiltrated weak surface. Under the steady seepage condition, the infiltrated weak surface has Self-healing characteristics, but after the healing of the permeability coefficient increased significantly. The osmotic stability of the normal consolidated specimens under high consolidation pressure did not change significantly after shearing. The infiltration stability of the overconsolidated samples with low consolidation pressure is significantly reduced, and the infiltration destruction is in the form of hydraulic wedging effect splitting the infiltrated weak surfaces under the condition of head swell, resulting in the erosion erosion.