土石混合体地层中基坑开挖对邻近既有隧道影响  

Influence of deep excavation on adjacent tunnel in soil-rock mixtures

作　　者：杨波[1,2] 谭勇[1,2] YANG Bo;TAN Yong(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering(Tongji University),Ministry of Education,Shanghai 200092,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]岩土及地下工程教育部重点实验室(同济大学),上海200092

出　　处：《哈尔滨工业大学学报》2021年第11期46-58,共13页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(41672269)。

摘　　要：为解决土石混合体地层中基坑开挖引起的隧道响应问题,基于离散单元法采用数值模拟手段进行研究。采用颗粒流数值计算软件PFC2D对土石混合体微观结构、隧道管片结构及基坑围护结构进行精细化建模及施工过程模拟,并针对隧道位于基坑开挖引起的主动土压力区及被动土压力区两类位置条件下,地层含石率w对基坑开挖引起的隧道结构响应影响规律进行系统性研究。结果表明:隧道位于基坑开挖主动土压力区时,量值大于60%前提下的含石率提升导致隧道周围逐渐形成具备较好抗剪性能的连续块石骨架体,从而抑制侧面开挖引起的隧道结构响应。隧道位于基坑开挖被动土压力区时,量值小于75%前提下的含石率的提升对上方开挖引起的隧道结构响应起到抑制作用;含石率大于75%时,含石率的提升无法为上方开挖引起的隧道结构响应提供抑制作用。To tackle the response problem of existing tunnel induced by adjacent excavation in soil-rock mixtures,numerical simulation tests based on discrete element method were utilized for investigation.By using the particle flow code software PFC2D,the micro structure of the soil-rock mixture,the tunnel lining structure,and the pit retaining structure were finely modeled,and the construction process was simulated.The influences of the rock content(w)on the responses of tunnel lining due to excavation nearby in the cases of different tunnel locations were systematically investigated.Results show that when the tunnel was located in the active earth pressure zone,with the value of w exceeded 60%,the increase in w resulted in the formation of rock skeleton around the tunnel segment,which decreased the tunnel responses induced by lateral excavation.When the tunnel was located in the passive earth pressure zone,as the value of w was lower than 75%,the excavation-induced tunnel responses started to decrease with the increase in the value of w;when the value of w exceeded 75%,such effect on tunnel responses induced by excavation above the tunnel would lose efficacy.

关 键 词：隧道 基坑开挖 土石混合体 含石率 

分 类 号：TU45[建筑科学—岩土工程]