摘要
在浅埋硬岩隧道中,地层拱效应对隧道稳定性具有显著影响,明确地层拱效应与隧道支护的相互作用机制,对于隧道支护力的确定意义重大。基于地层拱传递效应,构建适用于浅埋隧道层叠拱传递效应的力学模型,通过分析单层拱的主应力偏转与侧限力,推导出层叠拱应力传递的计算方法,并结合松动区内微分岩条上主应力的分布特征,利用极限平衡分析法得到浅埋硬岩隧道在稳定状态下支护力的计算公式。以青岛地铁6号线工程为背景,进行模型试验和现场监测,对计算方法的适用性进行了验证。结果表明:(1)参数敏感性分析表明,随着内摩擦角的增加,支护力逐渐减小,当隧道埋深不超过最大荷载传递区厚度(即H≤2.4B)时,随着埋深的增大,支护力逐渐增加,此外,随着层叠拱层数n的增加,支护力对其的敏感性降低;(2)主动支护的实施增加了围岩约束作用,在显著提升隧道围岩力学性能的基础上,进一步提高了隧道的临界失稳荷载等级,相较于被动支护,增强层叠拱的应力传递效应使围岩的承载能力提高了11.9%;(3)不同模式下隧道支护力的预测值与实测值平均相对误差均在20.9%以内,表明考虑层叠拱传递效应的隧道支护力预测值与实测值吻合度较高,验证了该支护力计算方法的准确性和适用性。研究成果为浅埋硬岩隧道工程安全设计与评价提供了重要参考。
In shallow buried hard rock tunnels,the ground arching effect has a significant impact on tunnel stability.It is of great significance to clarify the interaction mechanism between the ground arching effect and tunnel support for determining the tunnel support pressure.In this study,a mechanical model has been constructed that can be applied to the laminated arch transfer effect in shallow buried tunnels based on the ground arch transfer effect.By analyzing the principal stress deflection and lateral limiting force of single-layer arches,the method for calculating the stress transfer in laminated arches is derived,and combined with the distribution characteristics of the principal stresses on the differential rock strips in the loosening zone,the formula for calculating the support pressure of shallow buried hard rock tunnels in stable state is obtained by using the limit equilibrium analysis method.Modelling tests and field monitoring are carried out to verify the applicability of the calculation method in the Qingdao Metro Line 6 project.The results show that:(1)The parametric sensitivity analysis indicate that the support pressure gradually decreases with the angle of internal friction.When the tunnel depth does not exceed the thickness of the maximum load transfer zone(namely H≤2.4B),the support pressure gradually increases with the tunnel depth,and the sensitivity of the support pressure decreases with the layers of laminated arches n.(2)The implementation of active support enhances the constrain effect of the surrounding rock,which further improves the critical instability load rating of the tunnel on the basis of significantly enhancing the mechanical properties of the tunnel's surrounding rock.Compared with passive support,the stress transfer effect of the enhanced laminated arch increases the load carrying capacity of the surrounding rock by 11.9%.(3)The average relative errors between the predicted and measured tunnel support pressure under different modes are within 20.9%,which indicates that the pred
作者
秦哲
刘文龙
武发宇
韩继欢
李为腾
冯强
刘永德
QIN Zhe;LIU Wenlong;WU Fayu;HAN Jihuan;LI Weiteng;FENG Qiang;LIU Yongde(College of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;Shandong Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Shandong University of Science and Technology,Qingdao,Shandong 266590,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第9期2165-2177,共13页
Chinese Journal of Rock Mechanics and Engineering
基金
山东省自然科学基金资助项目(ZR2023QE048)
自然资源部滨海城市地下空间地质安全重点实验室开放基金(BHKF2022Y03)。
关键词
隧道工程
浅埋硬岩
模型试验
理论解析
拱效应
支护压力
tunneling engineering
shallow buried hard rock
model test
theoretical analysis
arching effect
support pressure
