分段循环荷载作用下二维非饱和土固结特性分析  

ANALYSIS OF TWO-DIMENSIONAL PLANE STRAIN CONSOLIDATION CHARACTERISTICS FOR UNSATURATED SOILS UNDER PIECE-WISE CYCLIC LOADING

作　　者：张添 汪磊[1] 沈思东 ZHANG Tian;WANG Lei;SHEN Sidong(School of Urban Railway Transportation,Shanghai University of Engineering Science,Shanghai 201620,China)

机构地区：[1]上海工程技术大学城市轨道交通学院,中国上海201620

出　　处：《工程地质学报》2022年第4期1010-1018,共9页Journal of Engineering Geology

基　　金：国家自然科学基金青年科学基金项目(资助号:41807232).

摘　　要：基于Dakshanamurthy和Fredlund提出的二维非饱和土固结理论,利用Fourier正弦级数展开、Laplace变换,分别给出了分段循环荷载作用下二维非饱和土固结问题的超孔隙气压力、超孔隙水压力和沉降的半解析解,并应用退化法验证了本文所得半解析解的正确性。然后,结合3种具体的荷载形式,分析了分段循环荷载作用下气相与液相渗透系数之比(k_(a)/k_(w))、水平方向与竖直方向渗透系数之比(k_(x)/k_(z))和荷载特征参数(a)对二维非饱和土固结特性的影响。结果表明:k_(a)/k_(w)和k_(x)/k_(z)的增大均会加速固结沉降进程;荷载特征参数越大,沉降发展越早,沉降值越小;二维非饱和土固结特性受分段循环荷载作用影响明显。因此,在实际施工过程中改变施工速度和设置径向排水装置可有效控制二维条件下非饱和土体的固结过程,该研究成果可为非饱和土地基的设计和施工提供重要理论依据。On basis of the Dakshanamurthy and Fredlund's 2D plane strain consolidation theory of unsaturated soils,the Fourier sinusoidal series expansion and Laplace transformation are adopted to give the semi-analytical solution of excess pore-air pressure,excess pore-water pressure and settlement considering the piece-wise cyclic loading,and the degenerate method is applied to verify the correctness of the semi-analytical solution obtained in this paper.Then,combined with three specific piece-wise cyclic loads,the influence on the consolidation of unsaturated soils are analyzed with the change of permeability coefficient ratio(k_(a)/k_(w)、k_(x)/k_(z))and load characteristic parameters(a).The results investigated in this paper show that the settlement will be accelerated by amplifying the value of k_(a)/k_(w)or k_(x)/k_(z).The loading parameter can speed up the consolidation and result in a smaller settlement.The 2D plane strain consolidation of unsaturated soils is obviously affected by the piece-wise cyclic loading,therefore the consolidation process of unsaturated soils can be effectively controlled by changing the construction speed and setting the radial drainage device in the actual construction process,that is,the research results in this paper can provide important theoretical basis for the design and construction of unsaturated soils foundation.

关 键 词：非饱和土 二维固结 分段循环荷载 半解析解 LAPLACE变换 

分 类 号：TU447[建筑科学—岩土工程]