循环荷载下结构性黏土的动力特性试验研究

天然沉积黏土大多具有结构性,我国沿海地区广泛分布着深厚的软黏土层,沿海地区的机场、高速公路、地铁等大型交通工程都建在软黏土地基上。天然软黏土由于结构性表现出与重塑土不同的工程性状,通过开展湛江原状黏土和重塑黏土的循环三轴试验,对循环荷载作用下湛江黏土的动变形、动强度和动孔压特性进行系统性的试验研究。结果表明,结构性黏土在循环荷载作用具有脆性破坏特征,固结压力增长造成的土体结构破坏对天然黏土动力特性的影响较大,随着固结压力增大,原状黏土的动力变形特性逐渐趋于重塑土,原状土和重塑土在不同围压下的动强度曲线差异性十分明显,且结构性某种程度上抑制了原状土的动孔压发展。

Experimental study on dynamic characteristics of structured clay under cyclic loading

Natural sedimentary clay can be regarded as structured clay, the natural soft clays are widely distributed in coastal areas in China. Large transportation projects such as the airport, the highway and the subway in the coastal areas are all built on the soft clay foundation. Natural soft clay shows different engineering properties from remolded clay due to its structure, through the cyclic triaxial tests of undisturbed clay and remolded clay in Zhanjiang, the dynamic deformation, dynamic strength and dynamic pore water pressure of clay under cyclic loading are studied. The results show that the brittle failure of structured clay under cyclic loading has been revealed, and the structural damage caused by the increasing consolidation pressure has a great influence on the dynamic characteristics of natural clay. With the increase of consolidation pressure, the dynamic deformation characteristics of undisturbed clay gradually tend to become the deformation characteristics of remolded clay. The dynamic strength curves of undisturbed clay and remolded clay under different confining pressures are quite different, and the development of dynamic pore water pressure of undisturbed clay is restrained by the structure.