摘要
针对深埋小净距隧道围岩压力计算存在中夹岩柱安全系数取值不准确的问题,从隧道施工过程中先行隧道开挖支护完成,后行隧道开挖但支护结构尚未闭合的状态出发,计算中夹岩柱极限承载力,采用强度折减法计算中夹岩柱安全储备系数,推导中夹岩柱对小净距隧道围岩压力分担作用表达式,建立考虑中夹岩柱安全储备的深埋小净距隧道围岩压力计算方法,通过算例验证该方法的合理性,分析净距对隧道围岩压力的影响。研究结果表明:本研究提出的围岩压力计算方法考虑了岩体参数、隧道跨度、工法等因素对中夹岩柱安全储备系数的影响,能更准确反映中夹岩柱对小净距隧道围岩压力的分担作用,某单洞四车道公路隧道Ⅳ级围岩段修正的中夹岩柱承载力为10324 kN/m,拱顶竖向围岩压力为264 kPa;某两车道公路隧道Ⅴ级围岩段修正的中夹岩柱承载力为2430 kN/m,拱顶竖向围岩压力为251 kPa。修正算法均实现了对实测围岩压力的包络,并且较规范值分别减小了6%和29%。根据本研究提出的算法,Ⅲ级围岩段四车道、三车道、两车道隧道围岩压力不受小净距影响的临界净距分别为0.6B4lanes、0.7B3lanes、0.7B2lanes,Ⅳ级围岩段分别为1.2B4lanes、0.9B3lanes、0.9B2lanes,Ⅴ级围岩段三车道和两车道隧道临界净距分别为1.8B3lanes和1.2B2lanes。
For the problem of inaccurate value of the safety factor of the middle rock pillar in the calculation of the surrounding rock pressure in deep buried neighborhood tunnels,this paper calculated the ultimate bearing capacity of the middle rock pillar from the state that the excavation and support of the first tunnel was completed while the later one was not supported integrality yet,and the strength reduction method was used to calculate the safety reserve factor of the middle rock pillar,deduced the expression of the sharing effect of the middle rock pillar on the surrounding rock pressure of the neighborhood tunnels,and the method of calculating the surrounding rock pressure in deep buried neighborhood tunnels considering the safety reserve of the middle rock pillar was established.The reasonableness of the calculation method of the surrounding rock pressure in this paper was verified by examples,and the influence of the distance on the surrounding rock pressure of the tunnel was analyzed with the calculation method.The results showed that the proposed method of calculating the surrounding rock pressure took into account the influence of rock parameters,tunnel span,excavation method and other factors on the safety reserve factor of the middle rock pillar,which could more accurately reflect the sharing effect of the middle rock pillar on the surrounding rock pressure of neighborhood tunnel than the calculation method of determining the safety factor of the middle rock pillar based on the experience of the current specification;the corrected load capacity of the middle rock pillar in the four-lane tunnel with gradeⅣsurrounding rock was 10324 kN/m,the maximum vertical surrounding rock pressure of the vault was 264 kPa,the corrected load capacity of the middle rock pillar in the two-lane tunnel with grade Ⅴ surrounding rock was 2430 kN/m,the maximum vertical surrounding rock pressure of the vault was 251 kPa,achieving the envelope of the measured value and reducing 6% and 29% respectively compared with the specif
作者
罗彦斌
王思涵
陈建勋
王传武
LUO Yanbin;WANG Sihan;CHEN Jianxun;WANG Chuanwu(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)
出处
《山东大学学报（工学版）》
CAS
CSCD
北大核心
2024年第3期81-93,共13页
Journal of Shandong University（Engineering Science）
基金
国家自然科学基金资助项目(51978065,52278394)
陕西省杰出青年科学基金资助项目(2020JC-28)。
关键词
隧道工程
深埋小净距隧道
围岩压力
中夹岩柱
强度折减法
tunnel engineering
deep buried neighborhood tunnel
surrounding rock pressure
middle rock pillar
strength reduction method
