基于Timoshenko梁理论的隧道隔水岩体安全厚度计算方法  

Calculation Method for Safe Thickness of Water Insulation Rock in Tunnelling Based on Timoshenko Beam Theory

作　　者：郑晓悦 施成华[1,2,3] 王祖贤 于国亮 郑可跃 ZHENG Xiaoyue;SHI Chenghua;WANG Zuxian;YU Guoliang;ZHENG Keyue(National Engineering Research Center of High-speed Railway Construction Technology,Central South University,Changsha 410075;China Railway Group Limited,Beijing 100039;School of Civil Engineering,Central South University,Changsha 410075;No.4 Engineering Co.,Ltd.of China Railway 17th Bureau Group Co.,Ltd.,Chongqing 401121)

机构地区：[1]中南大学高速铁路建造技术国家工程研究中心,长沙410075 [2]中国中铁股份有限公司,北京100039 [3]中南大学土木工程学院,长沙410075 [4]中铁十七局集团第四工程有限公司,重庆401121

出　　处：《现代隧道技术》2023年第4期14-22,共9页Modern Tunnelling Technology

基　　金：中国中铁股份有限公司科技研究开发计划项目(2021-重点-09);国家自然科学基金(52178402).

摘　　要：考虑隧道周围隔水岩体在溶腔泥水压力作用下的弯曲效应和剪切效应,基于Timoshenko梁理论,建立隧道隔水岩体安全厚度的解析计算模型,依据抗弯强度准则、抗剪强度准则推导最小安全厚度计算方法,并基于工程实例对隔水岩体安全厚度解析模型的影响因素进行系统分析。结果表明,溶腔直径对隔水岩体最小安全厚度影响最为明显;隔水岩体最小安全厚度随着隧道埋深、溶腔直径和溶腔水压力的增大而增大;随着隧道埋深和溶腔水压力的增加,相较于剪切破坏,隔水岩体更易发生弯曲破坏;随着溶腔方位角的增大,隔水岩体最小安全厚度先减小后增大,减小的速率先增大后减缓,最小安全厚度在溶腔位于隧道顶部时最大,在溶腔位于隧道底部时最小。与既有研究进行比较,发现同时考虑岩梁弯曲效应和剪切效应影响的隔水岩体最小安全厚度计算方法,能更有效地反映溶腔-隧道间岩梁的变形特征,具有良好的实用性。Considering the bending effect and the shear effect of the water insulation rock mass around the tunnel under the pressure of the mud water in the karst cavity,an analytical calculation model of the safe thickness of the water insulation rock of the tunnel is established based on the Timoshenko beam theory,the calculation method of the minimum safe thickness is derived as per the flexural strength criterion and the shear strength criterion,and the influencing factors of the analytical model for the safe thickness of the water insulation rock are systematically analyzed based on project cases.The results indicate that the diameter of the karst cavity has the most significant impact on the minimum safe thickness of the water insulation rock.The minimum safe thickness of the water insulation rock increases with the rise of tunnel burial depth,cavity diameter,and cavity water pressure.With the increase of tunnel burial depth and water pressure in the karst cavity,the water insulation rock is more prone to bending failure compared with shear failure.As the azimuth angle of the karst cavity increases,the minimum safe thickness of the water insulation rock first decreases and then increases,the rate of reduction first increases and then slows down,the maximum safe thickness value occurs when the karst cavity is located at the top of the tunnel,and there is the minimum safe thickness value when the karst cavity is located at the bottom of the tunnel.Compared with existing researches,it is found that the calculation method for the minimum safe thickness of water insulation rock,in which the impact of both bending and shear effects of rock beam is considered,can more effectively reflect the deformation characteristics of rock beams between the karst cavity and the tunnel,and is of good practicality.

关 键 词：富水隧道 隔水岩体 Timoshenko梁模型 安全厚度 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]