软硬不均地层盾构隧道荷载模式研究  

Study on Load Mode of Shield Tunnel in Soft-Hard Heterogeneous Ground

作　　者：石钰锋[1,3] 张涛 阳军生[2] 蒋亚龙 胡梦豪 代文超 SHI Yufeng;ZHANG Tao;YANG Junsheng;JIANG Yalong;HU Menghao;DAI Wenchao(State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University,Nanchang Jiangxi 330013,China;School of Civil Engineering,Central South University,Changsha Hunan 410083,China;Jiangxi Architectural Design Institute Co.,Ltd.,East China Jiaotong University,Nanchang Jiangxi 330013,China)

机构地区：[1]华东交通大学轨道交通基础设施性能监测与保障国家重点实验室,江西南昌330013 [2]中南大学土木工程学院,湖南长沙410083 [3]华东交通大学江西建筑设计院有限公司,江西南昌330013

出　　处：《中国铁道科学》2024年第5期123-134,共12页China Railway Science

基　　金：国家自然科学基金资助项目(42177162,42267022);江西省自然科学基金资助项目(20212BAB214009)。

摘　　要：系统考虑隧道埋深、滑移面形式、侧压力系数与地层的关联,提出一种适用于软硬不均地层的盾构隧道荷载模式。对于浅埋隧道,基于椭球体理论推导极限状态下滑移面为椭圆的侧压力系数及竖向松动土压力表达式,并构建力学平衡方程推导侧压力计算式;对于深埋隧道,考虑软硬不均地层突变性并对太沙基理论滑移面宽度进行合理修正,推导对应的围岩压力计算式;再结合软硬不均地层分界线位于隧道水平中线上方、下方2类典型工况,推导出隧底反力表达式;最后结合工程实例对所提荷载模式进行验证。结果表明:与修正惯用法荷载体系相比,所提方法得到的软土-硬土隧道顶部、下半拱竖向土压力与实测值的误差分别缩小74%和172%;相较于软土-硬土隧道,该方法应用于土层-岩层隧道时,计算得到的下半拱竖向土压力、隧底侧向土压力与实测值的误差更小,即所提荷载计算模式更符合隧道实际受荷状态,且当隧道埋深与开挖直径之比较大以及下部地层越坚硬时,其适用性越强。A load mode suitable for shield tunnels in soft-hard heterogeneous ground was proposed,which systematically considered the relationship between tunnel depth,the form of slip surface,lateral pressure coefficient and the ground.For shallow tunnels,the lateral pressure coefficient and vertical loose earth pressure expression for the elliptical slip surface at ultimate limit state were deduced based on ellipsoid theory,and the mechanical equilibrium equation was constructed to derive the lateral pressure calculation formula.For deep tunnels,the width of slip surface in Terzaghi’s theory was reasonably corrected considering the mutation of softhard heterogeneous ground,and the corresponding formulas of surrounding rock pressure were derived.Additionally,combined with two typical working conditions that the boundary of soft-hard heterogeneous ground is located above and below the horizontal middle line of the tunnel,the expression of the reaction force at the tunnel bottom was derived.Finally,the proposed load mode was verified by combining with engineering examples.The results show that compared with the load system of the modified routine method,the error between the vertical earth pressure at the top and lower half arch of soft soil-hard soil tunnels obtained by the proposed method and the measured value is reduced by 74%and 172%,respectively.However,compared with soft soil-hard soil tunnels,when this method is applied to soil-rock tunnels,the error between the calculated vertical earth pressure of the lower half arch and the lateral earth pressure at the tunnel bottom and the measured value is smaller.Namely,the proposed load calculation mode aligns better with actual tunnel loading conditions,particularly in scenarios with greater tunnel depth-to-diameter ratios and firmer lower ground,demonstrating its increased suitability.

关 键 词：盾构隧道 软硬不均地层 围岩压力 滑移面 荷载模式 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]