考虑刀土摩擦的砂土盾构隧道开挖面支护压力计算方法  

Calculation method of supporting pressure of shield tunnel excavation face in sand considering friction between cutter and soil

作　　者：应宏伟 吕忠泽[1] YING Hongwei;LÜZhongze(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210024,China;Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210024 [2]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058

出　　处：《中南大学学报（自然科学版）》2024年第3期1082-1091,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51678523);中央高校基本科研业务费资助项目(B200201012);浙江省建设科研项目(2018K119)。

摘　　要：确定盾构隧道开挖面极限支护压力是隧道工程中的核心问题之一。现有研究一般忽略盾构刀盘与主动极限状态时开挖面前方失稳土体间的摩擦效应,导致计算结果偏保守。为了解决此问题,首先,基于梯形楔形体模型,考虑盾构开挖掌子面与前方被切削土体之间的竖向摩擦力、楔形体与上方土柱之间因相对错动引起的横向摩擦力以及隧道埋深对极限支护压力的影响,推导了砂土地层盾构开挖面的极限支护压力计算公式;其次,通过与其他理论方法及试验结果进行对比,验证了本文方法的合理性;最后,讨论了刀土摩擦力在不同工况下对盾构开挖面极限支护压力的影响规律。研究结果表明:在其他参数不变时,开挖面极限支护压力随着刀土外摩擦角增大而逐渐减小,与刀土外摩擦角近似呈线性关系;刀盘土体间摩擦力对维持盾构开挖面稳定具有有利影响,对开挖面极限支护压力的影响不可忽略;适当增大刀盘与前方土体间的外摩擦角可有效增加开挖面的极限稳定性;刀土摩擦力对浅埋情况的盾构隧道开挖面极限支护压力的影响要明显比深埋情况的影响大,在选择盾构掘进刀具时应重点考虑埋深的影响。The determination of the face limit supporting pressure is one of the key problems in tunnelling engineering.The friction between cutter and soil is generally ignored,and the calculation results of supporting pressure are conservative.In order to solve the problem,firstly,by considering the influences of the vertical friction between the shield cutter and the cut soil,the horizontal friction between the wedge and the upper soil,and the tunnel depth on the limit supporting pressure,a formula to calculate the limit supporting pressure in sand strata was deduced via trapezoidal wedge model.Secondly,the rationality of the proposed method was verified by comparing with other theoretical results and experimental results.Finally,the influence of friction between cutter and soil on the face limit supporting pressure under different conditions was discussed by parameter analysis.The results show that when other parameters remain unchanged,the face limit supporting pressure decreases almost linearly with the increase of the friction angle between cutter and soil.The friction between cutter and soil has positive influence on the face stability,and the influence on the limit supporting pressure can not be ignored.The stability of the excavation face can be effectively enhanced by properly increasing the friction angle between cutter and soil.The influence of soil-cutter friction on the limit supporting pressure in shallow tunnels is obviously greater than that in deep tunnels,which should be considered in cutter selection of the shield tunnelling.

关 键 词：盾构隧道 砂土地层 支护压力 楔形体模型 土拱效应 

分 类 号：TU43[建筑科学—岩土工程]