南京河西淤泥质粉质粘土卸荷回弹变形研究

通过大量室内固结回弹试验,研究了南京河西地区淤泥质粉质粘土的卸荷回弹变形规律。固结-回弹-再压缩曲线表明该地区淤泥质粉质粘土的弹性变形要比其塑性变形量小得多,卸荷再压缩后,土体的压缩性也明显降低;通过分析卸荷比和回弹率、回弹应变以及回弹模量的关系曲线,确定了该地区淤泥质粉质粘土的临界卸荷比和极限卸荷比指标,从而可以确定开挖卸荷的影响深度范围。卸荷回弹变形随着卸荷滞留时间的增长,有先增大后减小的特点。试验结果表明,在卸荷与加荷作用下,土体的变形特性、变形模量有着明显差别。

Research on Unloading Rebound Deformation of Muddy Silty Clay at Hexi District in Nanjing City

With the rapid development of economic construction,the rebound deformation analyses are needed in many engineering projects.Through large numbers of consolidation-rebound tests,rebound deformation characteristics of muddy silty clay at Hexi district in Nanjing city under unloading have been studied.It indicates that the elastic deformation of muddy silty clay is much smaller than its plastic deformation and the compressibility of muddy silty clay is reduced significantly when it is compressed again after unloading.By analyzing the relationships of resilience ratio,resilience strain and resilience modulus to unloading ratio,the critical ratio and the ultimate ratio that can be used to estimate the depth of unloading influence are confirmed.The rebound deformation under unloading increases with the residence time before decrease.The test results show that the behaviors of deformation and deformation modulus under unloading conditions are much different from those under loading conditions.