人工制备初始应力各向异性结构性土方法探讨

Investigation on artificially structured soils with initial stress-induced anisotropy

通过对结构性黏土的研究可以掌握天然土受荷过程中的变形破坏过程,从而为考虑土结构性的结构物的设计、地基加固等提供依据。近年来随着高、深和大型建筑的兴建,结构性黏土的研究变得尤为重要。天然土都具有结构性和各向异性。发展了一种能够考虑初始应力各向异性影响的结构性土的人工制样方法。通过对原料粉质黏土中添加水泥形成颗粒之间的胶结作用,添加盐粒并溶解后形成大孔隙组构分布和在水化过程中的侧限应力状态的结构性土样的端部施加竖向荷载,从而人工制备了具有初始应力各向异性的结构性土样。然后对初始均质结构性土样、初始应力各向异性结构性土样和重塑土样进行了三轴固结排水剪切试验,初步分析了初始应力对结构性土样的应力-应变特性的影响和初始应力各向异性结构性土的破损机制。

The deformation and failure process of natural soil under loading can be obtained by research on structured clay ,on which the design of construction and soil improvement can be based when the structural influence is considered. With the construction of high, deep and great buildings, the research on the structured soil has recently become more and more important. Natural soils are structured and anisotropic. A new method is developed here to prepare artificially structured soils with initial stress-induced anisotropy. Silty clays are mixed with cements, salt grains and kaolin soils to form structured soil samples with initial stress-induced anisotropy. The bonding between soil particles can be formed by the hydration of cement, the big pore distribution can be produced by the dissolution of salt grains, and the initial stress-induced anisotropy can be developed by applying external forces on the ends of the samples with confining pressure states during the process of hydration. Triaxial shear tests under drained conditions are performed on initial uniform structured soil samples, initial stress-induced anisotropic structured soil samples and reconstituted soil samples. The influence of initial stress on the stress-strain properties of structured soils are analyzed and the breakage mechanism of structured soils with initial stress-induced anisotropy is also investigated.