摘要
为解决黄土隧道因不均匀荷载导致的支护结构安全性能降低问题,以中国已修建的27座浅埋黄土隧道的55个监测断面实测数据为基础,阐述了不同地理区划下浅埋黄土隧道围岩压力分布形态;联合数值计算和模型试验,揭示了浅埋黄土隧道不均匀荷载产生的原因,给出了隧道荷载调控技术,分析了调荷技术的实施效果。结果表明:浅埋黄土隧道围岩压力主要呈蝴蝶状分布,拱脚和拱圈60°位置普遍出现应力集中现象;围岩压力平均值为112 kPa,中位数为68 kPa,拱脚和拱圈60°位置对应荷载可达拱顶荷载的1.9~2.2倍和1.6~1.9倍;隧址区由黏质黄土、一般黄土到砂质黄土过渡,围岩压力蝶状分布愈发显著;地层不均匀沉降、破裂面不断扩展和相应位置较弱的土体强度等是浅埋黄土隧道不均匀荷载产生的主要原因,通过在隧道拱肩和拱脚一定位置施作“注浆小导管+注浆加固层”组合的荷载调控层,可实现对围岩压力的调控;调荷后的拱肩和拱脚荷载降幅20%~30%,拱顶土体沉降变形减少10%~20%,支护结构拱顶受拉得以缓解,拱肩和边墙侧受压减弱。所提出的荷载调控技术可改善支护结构受力,达到了较好效果。
To address the issue of decreased safety performance of support structure in loess tunnels due to uneven loading,this study was based on the measured data from 55 monitoring sections of 27 shallow-buried loess tunnels in China.It elucidated the distribution patterns of surrounding rock pressure in shallow-buried loess tunnels under different geographical zones.By combining numerical calculation numerical and model test,the study revealed the causes of uneven loading in shallow-buried loess tunnels and proposed tunnel load control techniques.Additionally,the effectiveness of these load control techniques was analyzed.The results show that the surrounding rock pressure of shallow-buried loess tunnels is mainly distributed in a butterfly shape,with stress concentration commonly observed at the 60°position of the arch and arch foot.The average value of surrounding rock pressure is 112 kPa,with a median value of 68 kPa.The loads at the arch foot and the 60°position of the arch circle can be up to 1.9-2.2 and 1.6-1.9 times the load of the vault,respectively.When the tunnel is located in the transition from clayey loess area to general loess area and sandy loess area,the butterfly-shaped distribution of surrounding rock pressure becomes increasingly prominent.Uneven settlement of strata,continuous expansion of fracture surfaces,and weaker soil strength at corresponding locations are the main causes of uneven loading in shallow-buried loess tunnels.By applying a load control layer composed of“grouting small conduits+grouting reinforcement layer”at certain positions on the tunnel arch shoulder and arch foot,control of surrounding rock pressure can be achieved.Load control results in a reduction of approximately 20%-30%in the load on the tunnel arch shoulder and arch foot,the settlement deformation of the soil above the vault decreased by 10%-20%.The tension on the vault is alleviated,and the compression on the arch shoulder and side wall is weakened.The proposed load control technique effectively improves the stress
作者
来弘鹏
赵铭坤
刘禹阳
LAI Hong-peng;ZHAO Ming-kun;LIU Yu-yang(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Sinohydro Bureau 3 Co.Ltd.,Xi'an 710024,Shaanxi,China;School of Civil Engineering,Chang'an University,Xi'an 710061,Shaanxi,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2024年第11期181-193,共13页
China Journal of Highway and Transport
基金
国家自然科学基金项目(52278391)。
关键词
隧道工程
荷载调控
数理统计
模型试验
数值计算
围岩压力
tunnel engineering
load control
mathematical statistics
model test
numerical calculation
surrounding rock pressure
