摘要
基于半无限饱和土初值解,首次考虑了多种施工因素和先行、后行盾构位置及施工间隔不同对后行隧道土体二次扰动的影响,修正了现有饱和土双线盾构施工引起的土体变形计算公式,建立了先行、后行盾构任意空间位置动态施工的修正力学模型,并结合典型的伦敦饱和黏土工程案例进行验证分析。研究结果表明,修正后的土体变形解和Mindlin解、丁智解相比,其结果与实测曲线更接近,可以较为准确地反映盾构掘进过程中纵向、横向地表变形的特点。当双线隧道平行布置时,由于先行隧道的影响,后行隧道土体的滞后效应相对减弱,但先行、后行隧道的影响范围基本一致;隧道间距越小,二次扰动效应越强,沉降变化速率越快,地表沉降量越大,沉降槽峰值点也越接近坐标中心;当双线隧道斜交布置时,若隧道间距不变,则后行隧道位于侧上穿区间受到二次扰动影响随角度变化的速率最大,位于上穿与侧下穿区间的变化率近似相同,而位于下穿区间的变化率最小;当先行、后行隧道施工间隔不同时,发现双线盾构同时施工引起的地表沉降量最大,随着先行、后行隧道施工间隔加长,土体强度逐渐恢复,先行隧道对土体的扰动效应逐渐减弱,后行盾构施工引起的地表变形逐渐减小,导致总地表沉降量也逐渐变小。
A modified model of ground movement induced by twin-tunnel shield tunnelling based on the initial value solution of the semi-infinite saturated soil was proposed.Based on the influence of various construction factors,the different positions of the forward and backward shield machines and the construction intervals on the secondary disturbance of soil surrounding the downward tunnel,the calculation formula of soil deformation caused by the existing saturated soil double-track shield construction was revised.A modified mechanical model of dynamic construction at any spatial position of the forward and backward shield machines was established.The model was verified using the field data from the Crossrail tunnels bored in London Clay.The results show that the modified soil deformation solution,which is closer to the measured curve than the Mindlin solution and the solution of Ding Zhi,can more accurately reflect the characteristics of longitudinal and lateral surface deformation during shield tunneling.When the twin tunnels are arranged in parallel,due to the influence of the secondary disturbance effect of the preceding tunnel,the hysteresis effect on the soil surrounding the downward tunnel is reduced.The influence ranges of the upward and downward tunnelling are basically the same.Smaller tunnel spacing leads to stronger secondary disturbance effect,faster change rate of settlement,greater surface settlement and smaller distance from the peak point of the settlement trough to the center of the coordinate.When the twin tunnels are arranged obliquely,if the tunnel spacing remains unchanged,the downward tunnel is located in the side-up section.The rate of change of the secondary disturbance with the angle is the largest.The rate of change in the up-across and side-under-through sections is approximately the same,while the rate of change in the under-across section is the smallest.When the construction interval of the first and subsequent tunnels is different,the ground surface settlement is the largest.As the constru
作者
丁智
冯丛烈
董毓庆
徐涛
张默爆
DING Zhi;FENG Conglie;DONG Yuqing;XU Tao;ZHANG Mobao(Department of Civil Engineering,Zhejiang University City College,Hangzhou 310015,China;Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province,Hangzhou 310015,China;College of Civil Engineering,Shaoxing University,Shaoxing 312000,China;Shenzhen Municipal Engineering Corporation,Shenzhen 518109,China)
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2022年第3期158-170,共13页
Journal of the China Railway Society
基金
浙江省自然科学基金(LHZ20E080001)
浙江省重点研发计划(2017C03020,2020C01102)
杭州市科技计划(20191203B44)。
关键词
饱和土
双线盾构
不同位置
土体变形
扰动影响边界
saturated soil
twin-tunnel shield
different positions
soil deformation
disturbance affecting boundary
