基于横观各向同性的土工格栅增强地基力学特性研究  

Transverse isotropy-based study on mechanical characteristics of geogrid reinforced foundation

作　　者：彭木文 左双英[1,2] 杨朵环 杨国生 莫云川 PENG Muwen;ZUO Shuangying;YANG Duohuan;YANG Guosheng;MO Yunchuan(Key Laboratory of Karst Georesources and Environmental,Ministry of Education,Guizhou University,Guiyang 550025,Guizhou,China;College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,Guizhou,China)

机构地区：[1]贵州大学喀斯特地质资源与环境教育部重点实验室,贵州贵阳550025 [2]贵州大学资源与环境工程学院,贵州贵阳550025

出　　处：《水利水电技术（中英文）》2023年第3期135-143,共9页Water Resources and Hydropower Engineering

基　　金：国家自然科学基金(42167025);贵州省科学技术厅社会发展科技攻关项目(黔科合支撑[2017]2866)。

摘　　要：【目的】土工格栅加筋地基在水利、建筑、交通等工程应用广泛,其竖直方向和水平方向的力学特性是值得关注的焦点。为研究不同加筋间距、层数对土工格栅加筋地基竖向和水平向承载特性的影响,【方法】通过物理模拟浅层平板载荷试验,将土工格栅加筋地基视为横观各向同性介质,结合复合材料力学理论推导出了弹性参数的求解方法,同时考虑地基横观各向同性特征计算了竖向附加应力及沉降量。【结果】结果显示:400 kPa可作为地基极限荷载值,加筋5层、7层、16层在相同沉降位置的地基承载力分别提高了26%、39.2%、63.5%;在相同挡墙高度107 cm处,加筋5层、7层、16层工况相比无加筋工况水平位移减少了59%、66%、85%。【结论】结果表明:土工格栅加固地基后对土体的变形模量、剪切模量增强作用显著,而竖向泊松比变化较不明显;加筋地基的水平、竖向变形模量分别与加筋率之间存在较好的线性关系,采用横观各向同性模型推导计算的附加应力值接近试验值,计算的沉降量与试验值误差较小。研究成果可为类似实际工程设计提供一定的理论依据。[Objective]Geogrid reinforced foundation is widely applied to water conservancy,construction and transportation projects,of which the mechanical properties in vertical and horizontal directions are the focuses of attention,and then the effects of different reinforcement spacing and number of layers on the vertical and horizontal bearing characteristics of the geogrid reinforced foundation are studied herein.[Methods]Through physically simulating the shallow plate load test,the geogrid reinforced foundation is regarded as a transversely isotropic medium and the solution method of elastic parameters is deduced out in combination with the theory of composite material mechanics,while the vertical additional stress and settlement are calculated under the consideration of the transverse isotropic characteristics of the foundation.[Results]The result show that 400kPa can be taken as the ultimate load value of the foundation.The foundation bearing capacities with the reinforcements of 5,7 and 16 layers at the same settlement position are increased by 26%,39.2%,63.5%respectively,while the horizontal displacements under the working conditions with the reinforcements of 5,7 and 16 at the same retaining wall height of 107 cm are decreased by 59%,66%,85%if compared with those unreinforced working conditions.[Conclusion]The result show that the deformation modulus and shear modulus of the soil mass after reinforcing the foundation with geogrid are significantly enhanced,but the change of the vertical Poisson′s ratio is not so obvious,while better linear relationships of both the horizontal modulus and the vertical deformation modulus of the reinforced foundation are there with the reinforcement rate respectively.The calculated additional stress value derived from the transverse isotropic model is close to the test value and the error between the calculated settlement and the test value is less.The study result can provide certain reference for the design of the similar actual project concerned.

关 键 词：加筋地基 横观各向同性 浅层平板载荷试验 附加应力 地基沉降 

分 类 号：TU470.3[建筑科学—结构工程]