西昌某软土地层基坑变形分析及加固处理  

Treatment Measures and Deformation Analysis on Some High Sensitivity Formation Deep Excavation in Xichang

作　　者：章宁 孟宝华 邓宇 ZHANG Ning;MENG Baohua;DENG Yu(MCC Chengdu Surveying Geotechnical Research Institute Co.Ltd.,Chengdu 610023;The Third Hospital of Mianyang,Sichuan Mental Health Center,Mianyang 621000)

机构地区：[1]中冶成都勘察研究总院有限公司,成都610023 [2]绵阳市第三人民医院·四川省精神卫生中心,四川绵阳621000

出　　处：《土工基础》2024年第3期409-414,共6页Soil Engineering and Foundation

基　　金：中冶成都勘察研究总院有限公司科研课题(ZYCK2021-003)。

摘　　要：某基坑位于西昌某软土地层,基坑深约12 m,开挖至3 m左右出现严重变形。经对基坑周边环境条件及变形特征分析,发现地质条件差、降雨下渗土层饱和度增加及基坑空间效应是变形的主要诱因。经参数反演,基坑变形后土体抗剪强度参数仅剩勘察报告的1/3,通过锚索基本试验,锚固段每米轴向抗拔力标准值约为28.27 kN,在此基础上,经过专家论证,采取增加旋喷扩体锚索及角撑等措施,有效的保证了基坑变形收敛及正常运行,确保了工程建设顺利进行。A deep excavation project was in the highly sensitive soil layer area in Xichang,which is about 12m deep.Excessive lateral deformations in the supporting system were observed three meters after the excavation.Evaluations are performed on the adjacent environments and deformations,poor geological conditions,precipitations and the space effect of the deep excavation are the potential main factors of these serious deformations.Throughout the back analysis,the shear strength parameter of the soil mass after the excavation deformation hazard was only 1/3 of that presented in the geotechnical investigation report.Ac-cording to the load test of the ground anchor,the standard value of axial pull-out force per meter within the bond length was a-bout 28.27kN.A third-party expert panel discussion based on these results suggested that mitigation methods of"ground an-chor with expanded angle jet grouting"and"corner supporting"be used to control the deformations.These measures mitigated deformation effectively and the safety and smooth construction of the project were ensured.

关 键 词：深基坑 高灵敏性土 基坑变形 斜撑 基坑加固 

分 类 号：TU473[建筑科学—结构工程]