摘要
隧道浅埋段软弱围岩在开挖过程中易发生坍塌和涌水突泥等灾害。为明确隧道浅埋段软弱围岩地表高压旋喷加固机理及效果,以广东省云茂高速公路新屋隧道浅埋段软弱围岩地表高压旋喷加固为例,详细分析了地表高压旋喷对软弱围岩的整体加固作用及形成的“土拱效应”。通过对加固后的地表沉降、孔隙水压力、拱顶下沉、边墙收敛和围岩接触压力等现场监测数据进行分析,论证了地表高压旋喷对隧道浅埋段软弱围岩加固的可行性和效果。结果表明:经高压旋喷加固后,桩土之间通过摩阻力的作用将上覆土体自重逐步传递至边桩处,并最终传递至基岩层,桩土相互作用使得隧道开挖后的桩土复合体形成“土拱效应”,加固后围岩具有较好的自稳能力,掌子面塑性挤出模拟值仅为2.5 mm,掌子面前方桩体起到了很好的支挡作用;加固后地表沉降和围岩孔隙水压力较小,最大值仅为5.6 cm和15.5 kPa,隧道拱顶下沉和围岩接触压力最大值仅为4.6 cm和40 kPa,边墙收敛位移仅为2.8 cm;地表高压旋喷预加固能够有效改善围岩整体性,提高岩土体强度,降低围岩渗透性,有效保障了隧道浅埋软弱围岩段的施工安全;掌子面前方桩体的支挡作用,有效防止了隧道上台阶开挖时的塑性挤出和溜坍,且掌子面无明显塑性挤出。
The soft surrounding rock in the shallow-buried section of tunnel is prone to collapse, water gushing and mud bursting during excavation. In order to clarify the reinforcement mechanism and effect of surface high pressure jet grouting on soft surrounding rock in shallow-buried section of tunnel, taking the surface high pressure jet grouting reinforcement in shallow-buried section soft surrounding rock of Xinwu Tunnel of Yunfu-Maoming Expressway in Guangdong Province for example, the whole reinforcement effect of surface high pressure jet grouting on soft surrounding rock and the formation of “soil arching effect” are analyzed in detail. Based on the analysis of the field monitoring data of ground settlement, pore water pressure, crown subsidence, sidewall convergence and surrounding rock contact pressure after reinforcement, the feasibility and effect of surface high pressure jet grouting for soft surrounding rock reinforcement in shallow-buried section of tunnel are demonstrated. The result shows that(1) After the reinforcement by high pressure jet grouting, the self-weight of the overlying soil is gradually transferred to the side pile through the action of friction between pile and soil, and finally to the bedrock layer. The pile-soil interaction makes the pile-soil complex form “soil arching effect” after tunnel excavation, the surrounding rock has good self-stability ability after reinforcement, the plastic extrusion simulation value of the tunnel face is only 2.5 mm, and the pile in front of the tunnel face plays a good supporting role.(2) The ground settlement and pore water pressure of the surrounding rock are smaller after the reinforcement, the maximum values are only 5.6 cm and 15.5 kPa, the maximum values of tunnel vault subsidence and contact pressure of surrounding rock are only 4.6 cm and 40 kPa, and the convergent displacement of side wall is only 2.8 cm.(3) Surface high pressure jet grouting reinforcement can effectively improve the integrity of surrounding rock, improve the strength of r
作者
蔡敏
徐华
韩富庆
娄健
杨明兴
CAI Min;XU Hua;HAN Fu-qing;LOU Jian;YANG Ming-xing(Guangdong Yunfu-Maoming Expressway Co.,Ltd.,Guangzhou Guangdong 510623,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2023年第1期152-159,共8页
Journal of Highway and Transportation Research and Development
基金
交通运输部重点科技项目(2019-MS1-017)。
关键词
隧道工程
浅埋隧道
数值模拟
高压旋喷
现场监测
tunnel engineering
shallow-buried tunnel
numerical simulation
high pressure jet grouting
field monitoring
