岩溶区土洞基础稳定性解析研究  

Analytic Study on Stability of Soil Cave Foundation in Karst Area

作　　者：赵明华[1] 肖尧[1] 赵衡[1] 徐卓君[1] 胡倩[1] ZHAO Ming-hua;XIAO Yao;ZHAO Heng;XU Zhuo-jun;HU Qian(Institute of Geotechnical Engineering,Hunan University,Changsha Hunan 410082,China)

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《公路交通科技》2020年第6期36-43,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51478178,51068540)。

摘　　要：本研究旨在给出非均布、非对称基础荷载作用下圆形、椭圆形土洞稳定性评价方法。首先,根据岩溶区土洞基础承载特性,考虑条形基础埋深、土洞形状和地下水情况,建立了8种不同条件下的简化计算模型。其次,基于Boussinesq解、Mindlin解分别对作用于地层表面、地层内部的非均布基础荷载进行积分,求得条形基础荷载引起的地层应力。再次,基于复变函数法,通过映射函数将圆形、椭圆形土洞转换为复平面内的单位圆,采用保角变换、柯西积分等方法分别求得考虑地下水或不考虑地下水的圆形、椭圆形土洞在自重影响下的应力场。然后,将土洞在条形基础引起的应力场和在自重影响下的应力场进行叠加,便可求得基础荷载作用下含土洞地层中的应力场。基于此,便可进一步求得含空洞地层中任意一点最大、最小主应力。在Mohr-Coulomb屈服准则的基础上,选取离基础较近的土洞周围的关键点,并对这些关键点进行稳定性验算,从而对基础荷载作用下土洞整体的稳定性进行评价。最后,采用工程算例验证了本研究方法的可行性与正确性,以期为岩溶区土洞基础初步设计提供参考。值得注意的是,本研究应力场的计算是基于弹性理论,并没有考虑土体由于塑性特征引起的变形,该部分对应力场的计算有一定影响,在今后的研究中还需进一步探讨。The aim of this research is to provide an assessment method for stability of circular and elliptical soil cave under non-uniformly and asymmetric distributed foundation loads.First,according to the characteristics of foundation of soil cave in karst area,considering the depth of strip foundation,the shape of soil cave and the condition of groundwater,8 simplified calculative models under different conditions are built.Second,using Boussinesq’s solution or Mindlin’s solution,the non-uniform foundation loads acting on the formation surface or interior are integrated,and the formation stress caused by strip foundation load are obtained respectively.Third,based on the complex function method,the circular and elliptical soil caves are transformed into unit circles in the complex plane by mapping functions,and the stress fields of circular and elliptical soil caves which considering groundwater or not under gravity are obtained by using conformal transformation and Cauchy integral.Then,the stress fields of soil cave caused by strip foundation and its gravity are superposed,thus the stress field in the formation with soil cave under foundation load can be obtained.On this basis,the maximum and minimum principal stresses at any point in the formation with cavities can be obtained.Selecting the key points around the soil cave near the foundation,the stability of these key points is checked based on Mohr-Coulomb yield criterion.Therefore,the soil cave stability under the foundation loading is evaluated.At last,the correctness and the feasibility of the proposed method are verified by engineering example to provide a guidance for preliminary designing soil cave foundation in karst area.It is worth noting that,the calculation of stress field here is based on elastic theory,and the deformation of soil due to plastic characteristics is not considered,which needs to be further studied in the future.

关 键 词：道路工程 岩溶区 复变函数法 土洞 稳定性 地层应力 

分 类 号：TU470[建筑科学—结构工程]