武汉地区厚互层土中基坑抗突涌破坏评价方法研究  

Study of evaluation method of anti-uprush stability of foundation pit with thick interbedded soil layers in Wuhan

作　　者：熊宗海 冯晓腊[1,2] 张红章 范卫琴[1,2] 程华强 XIONG Zonghai;FENG Xiaola;ZHANG Hongzhang;FAN Weiqin;CHENG Huaqiang(Wuhan Fengda Geological Engineering Ltd.,Wuhan,Hubei 430074,China;Department of Engineering,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China;Wuhan Bridge Engineering Co.,Ltd.,Wuhan,Hubei 430074,China)

机构地区：[1]武汉丰达地质工程有限公司,湖北武汉430074 [2]中国地质大学(武汉)工程学院,湖北武汉430074 [3]武汉市桥梁工程有限公司,湖北武汉430074

出　　处：《水文地质工程地质》2020年第2期134-140,共7页Hydrogeology & Engineering Geology

基　　金：武汉市市政建设集团有限公司科研项目(wszky201821);福建省中青年教育科研项目(2017)(JAT170538)。

摘　　要：针对武汉地区厚互层土基坑,考虑坑底厚互层土重力、摩擦力和黏聚力的实际情况,建立了基于厚互层土的基坑突涌计算模型,提出了厚互层土基坑突涌稳定性安全系数计算方法。以武汉华润万象城深基坑工程为例,将本文模型的计算结果与《建筑基坑支护技术规程》(JGJ120—2012)和现有文献计算结果进行了比较。结果表明:将厚互层土含水层看作多个薄层含水层并用压力平衡法判断突涌不稳定时,突涌不稳定区域仅局限于厚互层土顶部1~2 m范围内,故可以将厚互层土看作隔水层而非含水层。因为武汉地区绝大部分厚互层土厚度远超过2 m,因此规程计算结果偏于保守。考虑厚互层土的黏聚力、自重、摩擦力建立的基坑抗突涌稳定性分析模型,在本工程案例中计算得突涌安全系数为3.5,而同等场地条件下规范采用的压力平衡法计算突涌安全系数为1.5,本方法计算结果约为规范方法的2.2倍,因此按照本文方法计算结果制定坑底抗突涌破坏方案,将比只依靠土体自重来抵抗突涌破坏更符合工程实际、更经济,为重新定义互层土在基坑抗突涌方面的作用进行了有益探索。Aiming at the foundation pit with thick interbedded soil in Wuhan,considering the gravity,friction and cohesion of thick interbedded soil,a calculation model of anti-uprush of foundation pit with thick interbedded soil was established,and a calculation method of the anti-uprush stability of foundation pit with thick interbedded soil was proposed.Taking the foundation pit of Wuhan Huarun Wanxiang as an example,the calculation results of the model proposed in this paper are compared with the Technical Specification for Retaining and Protection of Building Foundation Excavations(JGJ120—2012)and existing literatures.The results show that when the thick interbedded soil was regarded as multiple thin aquifer layers and the pressure method is used to judge the uprush instability,the uprush instability area is only limited to the range of 1~2 m at the top of the thick interbedded soil,so the thick interbedded soil can be regarded as an impermeable layer instead of aquifer.Because most of the thick interbedded soil in Wuhan area is more than 2 m,the calculation results of the Technical Specification for Retaining and Protection of Building Foundation Excavations(JGJ120—2012)tend to be conservative.The safety factor of anti-uprush is calculated as 3.5 in the model of anti-uprush of foundation pit with thick interbedded soil which considering the gravity,friction and cohesion of thick interbedded soil,while the safety factor of anti-uprush calculated by the pressure balance method adopted by the code under the same site conditions is 1.5,the calculation result of anti-uprush stability model is about 2.2 times than the Technical Specification for Retaining and Protection of Building Foundation Excavations(JGJ120—2012).Therefore,the stability of anti-uprush at the bottom of the pit calculated by this method will be better than that calculated by this method.It is more practical and economical to rely on soil gravity to resist inrush damage,but this conclusion still needs to be tested by a lot of engineering practice.Thi

关 键 词：厚互层土 基坑突涌 计算模型 稳定安全系数 

分 类 号：TU46[建筑科学—结构工程]