摘要
粤港澳大湾区为中国经济活力最强的区域之一,在国家发展大局中具有重要战略地位。由于该区域广泛分布海积相和海陆交互相深厚软土,给工程建设带来了诸多困难,甚至造成巨大经济损失和人员伤亡。通过对广州南沙某基坑进行理论计算和数值模拟,结合对监测资料的详细分析,探讨广州南沙某深厚软土区综合管廊基坑破坏发生的成因和变形特征,所得结论如下:本基坑失稳破坏模式属于踢脚破坏和倾倒破坏的组合破坏模式,以踢脚破坏为主,基坑破坏位置桩顶水平位移整体向右,产生这种现象的原因是由于大型运输车辆在基坑左侧行驶,引起基坑单侧超载;受横撑的约束作用,基坑桩顶水平位移和竖向位移在基坑破坏前位移仍然比较小,不能有效的反映基坑的变形和安全情况,因此要重视基坑深层水平位移监测;深层水平位移最大位置主要集中在基坑深度6~11 m,基本处于基坑底部以下;深层水平位移的变形范围达到18 m左右深度,表明基坑开挖引起的支护桩变形影响范围达到坑底以下12m,变形影响深度和基坑深度的比值为3;基坑进行回填之后基坑位移明显收敛,表明回填可以有效抑制基坑变形的扩展,避免连续性破坏。
The Guangdong-Hong Kong-Macao Greater Bay Area is the most economically developed regions in China and has an important strategic position in national development.However,due to the extensive distribution of marine soft clay,it has brought many challenges to engineering construction.Based on the theoretical and numerical analysis and monitoring data in Nansha,Guangzhou.This paper discusses the cause of failure and deformation characteristics of a utility tunnel excavation.The research results show that the failure mode of this excavation belongs to the combined damage of kicking and dumping,mainly kicking damage.The horizontal displacement of the pile top points to right.The reasons for this phenomenon are that the distance between the vehicle and the excavation is too small and trucks are overload.Due to the support by the cross brace,the horizontal displacement and vertical displacement of steel sheet pile are still relatively small and stable before the excavation is destroyed,and cannot effectively reflect the safety of the excavation.Therefore,attention should be paid to the monitoring of the surrounding ground settlement and deformation of the deep horizontal displacement.The maximum deep horizontal displacement is at a depth of 6-11 m,which is below the bottom of the excavation.This deformation is different from that in the non-soft soil area.The deformation of the deep horizontal displacement reaches a depth of about 18 m,indicating that the deformation of the supporting pile caused by the excavation reaches 12 m below the bottom,and the ratio of deformation depth to the excavation depth is 3.The damaged location of the excavation should be backfilled in time.
作者
宋许根
SONG Xugen(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,Hubei 430063,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2023年第S01期3629-3642,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金重点项目(41630641)
住房和城乡建设部支撑产业转型升级重点研发项目(2020-K-155)
中铁第四勘察设计院集团有限公司重点科研攻关项目(2020K118)
关键词
土力学
南沙软土
综合管廊
软土基坑
破坏机制
soil mechanics
soft clay of Nansha
utility tunnel
soft soil excavation
failure mechanism
