上覆荷载作用下红黏土抗剪强度变化规律研究

Study on the change law of shear strength of red clay under overburden load

为了探究红黏土地区道路等地基工程建设中出现裂缝的原因,通过直剪试验对更加符合工程实际情况的上覆荷载作用下的红黏土抗剪强度变化规律进行研究。结果表明:无论有无上覆荷载,红黏土黏聚力、内摩擦角均随含水率的增大逐渐减小,随压实度的增加而逐渐增大,随干湿循环次数的增加逐渐减小;黏聚力受含水率、压实度影响的程度大于内摩擦角;同一条件下,上覆荷载作用下的红黏土黏聚力C、内摩擦角φ均大于无上覆荷载作用下的,且上覆荷载作用下的抗剪强度受含水率、压实度、干湿循环次数的变化幅度小于无上覆荷载作用下的。研究成果可为红黏土地区的道路等地基工程建设提供更加可靠的技术支撑。

In order to investigate the causes of cracks in road constructions such as red clay areas,the direct shear tests were used to study the change law of the shear strength index of red clay under the overburden load more in line with the actual conditions of the project.Regardless of whether there was an overburden load,the cohesion and internal friction angle in red day gradually decreased with the increase of water content,gradually increased with the increase of compaction degree,and gradually decreased with the increase of the number of dry and wet cycles;2)The degree of cohesion affected by the water content and compaction was greater than that by the internal friction angle;3)Under the same conditions,the cohesion C and the internal friction angleφof the red clay with the overburden load were greater than those without overburden,and the effect of water content,compaction,and the number of wet and dry cycles of the shear strength index under the effect of overlying load was smaller than that without overburden load.The research results could provide more reliable technical support for road engineering construction in red clay areas.