Case study on the overall stability of foundation pit slope with weak interlayer
LI Lianxiang1,2,3, LÜ Guiqing4, ZHANG Shangru1,2, ZHAO Yongxin1,2, WANG Chuhan1,2
1. School of Civil Engineering, Shandong University, Jinan 250061, Shandong, China; 2. Foundation Pit and Deep Foundation Engineering Research Center, Shandong University, Jinan 250061, Shandong, China; 3. Shandong High-Xin Geotechnical Engineering Co., Ltd., Jinan 250102, Shandong, China; 4. Jinan City Urban and Rural Construction Development Service Center, Jinan 250014, Shandong, China
Abstract: In the northern area of Jinan City, along the banks of the Yellow River, there was a layer of silty soil approximately 6 to 8 meters below the surface. A large number of landslides were observed in nearby excavations at this depth, demonstrating a different overall failure mode from the conventional circular sliding method for excavations. Based on extensive engineering landslide characteristics, a specific case analysis indicated that the slopes of excavations containing weak interlayers were subjected to a combined circular-plane overall failure mode. This conclusion was validated through numerical analysis using Plaxis finite element software. An analytical solution for the overall stability analysis of excavation slopes with weak interlayers was derived based on statics and moment equilibrium equations. The optimal support scheme was proposed and validated through numerical and monitoring data. The findings suggested that excavation slopes in geological units of the Yellow River alluvial plain in northern Jinan City were influenced by weak interlayers, exhibiting an overall failure mode of circular-plane sliding. The conventional circular sliding calculation method for excavation design posed safety risks. Therefore, the selection of excavation support structures should incorporate shear-resistant elements penetrating the weak interlayers to transform the circular-plane failure mode into circular sliding mode, thus ensuring excavation safety.
李连祥,吕桂青,张尚儒,赵永新,汪楚涵. 软弱夹层基坑圆弧-平面整体破坏模式分析与治理[J]. 隧道与地下工程灾害防治, 2024, 6(3): 1-11.
LI Lianxiang, LÜ Guiqing, ZHANG Shangru, ZHAO Yongxin, WANG Chuhan. Case study on the overall stability of foundation pit slope with weak interlayer. Hazard Control in Tunnelling and Underground Engineering, 2024, 6(3): 1-11.
[1] 山东大学, 济南市勘察测绘研究院. 济南市区岩土工程勘察地层层序划分标准: DB37/T 5131—2019[S]. 济南:山东大学出版社,2019. [2] 中国建筑科学研究院. 建筑基坑支护技术规程: JGJ 120—2012[S]. 北京: 中国建筑工业出版社, 2012. [3] 胡卸文. 无泥型软弱层带变形参数取值研究[J]. 岩土工程学报, 2000, 22(1): 109-112. HU Xiewen. Study on evaluation of deformation modulus of no-clay weak interbed[J]. Chinese Journal of Geotechnical Engineering, 2000, 22(1): 109-112. [4] 张晓平, 吴顺川, 张志增, 等. 含软弱夹层土样变形破坏过程细观数值模拟及分析[J]. 岩土力学, 2008, 29(5): 1200-1204. ZHANG Xiaoping, WU Shunchuan, ZHANG Zhizeng, et al. Numerical simulation and analysis of failure process of soil with weak intercalated layer[J]. Rock and Soil Mechanics, 2008, 29(5): 1200-1204. [5] 袁伟, 黄茂松, 刘怡林, 等. 含软弱夹层土坡稳定性的三维弹塑性数值模拟[J]. 郑州大学学报(工学版), 2012, 33(5): 1-4. YUAN Wei, HUANG Maosong, LIU Yilin, et al. Three-dimensional stability analysis of slopes with weak interlayer based on elastoplastic numerical method[J]. Journal of Zhengzhou University(Engineering Science), 2012, 33(5): 1-4. [6] 王浩然,黄茂松,刘怡林. 含软弱夹层边坡的三维稳定性极限分析[J].岩土力学,2013,34(增刊2):156-160. WANG Haoran, HUANG Maosong, LIU Yilin. Three-dimensional stability analysis of slope with weak interlayer[J].Geotechnical mechanics, 2013, 34(Suppl.2):156-160. [7] HUANG M S, WANG H R, SHENG D C, et al. Rotational-translational mechanism for the upper bound stability analysis of slopes with weak interlayer[J]. Computers and Geotechnics, 2013, 53: 133-141. [8] 王睿, 张嘎, 张建民. 降雨条件下含软弱夹层土坡的离心模型试验研究[J]. 岩土工程学报, 2010, 32(10): 1582-1587. WANG Rui, ZHANG Ga, ZHANG Jianmin. Centrifuge modeling of rainfall-induced deformation of slopes with weak layers[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(10): 1582-1587. [9] 汤祖平,李亮,赵炼恒,等.含软弱夹层边坡稳定性的极限分析上限解析[J].铁道科学与工程学报,2014,11(2):60-64. TANG Zuping, LI Liang, ZHAO Lianheng, et al. Upper limit analysis of slope stability with weak interlayer[J]. Journal of Railway Science and Engineering, 2014, 11(2): 60-64. [10] 皮晓清,李亮,唐高朋,等. 基于有限元极限上限法的含软弱夹层边坡稳定性分析[J].铁道科学与工程学报,2019,16(2):351-358. PI Xiaoqing, LI Liang, TANG Gaopeng, et al. Stability analysis for soil slopes with weak interlayers using the finite element upper bound limit analysis[J]. Journal of Railway Science and Engineering, 2019, 16(2): 351-358. [11] 黄茂松, 王浩然, 刘怡林. 基于转动-平动组合破坏机构的含软弱夹层土坡降雨入渗稳定上限分析[J]. 岩土工程学报, 2012, 34(9): 1561-1567. HUANG Maosong, WANG Haoran, LIU Yilin. Rotation-translation combined mechanism for stability analysis of slopes with weak interlayer under rainfall condition[J]. Chinese Journal of Geotechnical Engineering, 2012, 34(9): 1561-1567. [12] 邓东平,李亮.水平条分法下边坡稳定性分析与计算方法研究[J].岩土力学,2012,33(10):3179-3188. DENG Dongping, LI Liang. Analysis of slope stability and research of calculation method under horizontal slice method [J]. Rock and Soil Mechanics, 2012, 33(10): 3179-3188. [13] 李连祥, 刘嘉典, 李克金, 等. 济南典型地层HSS参数选取及适用性研究[J]. 岩土力学, 2019, 40(10): 4021-4029. LI Lianxiang, LIU Jiadian, LI Kejin, et al. Study of parameters selection and applicability of HSS model in typical stratum of Jinan[J]. Rock and Soil Mechanics, 2019, 40(10): 4021-4029. [14] 徐帮树,刘日成,李连祥,等.复合土钉墙支护设计参数敏感性分析及边坡变形规律研究[J].岩土力学,2011,32(增刊2):393-400. XU Bangshu, LIU Richeng, LI Lianxiang, et al. Study of slope deformation and parameters sensitivity in supporting design of composite soil nailing wall[J]. Rock and Soil Mechanics, 2011, 32(Suppl.2): 393-400. [15] 刘金龙, 栾茂田, 赵少飞, 等. 关于强度折减有限元方法中边坡失稳判据的讨论[J]. 岩土力学, 2005, 26(8): 1345-1348. LIU Jinlong, LUAN Maotian, ZHAO Shaofei, et al. Discussion on criteria for evaluating stability of slope in elastoplastic FEM based on shear strength reductiontechnique[J]. Rock and Soil Mechanics, 2005, 26(8): 1345-1348. [16] JANBU N. Application of composite slip surfaces for stability analysis[J]. European Conferrence on Stability of Earth, 1954, 3: 43-49. [17] WON J, YOU K, JEONG S, et al. Coupled effects in stability analysis of pile+slope systems[J]. Computers and Geotechnics, 2005, 32(4): 304-315. [18] 方健, 邓琴. 含软弱夹层顺层边坡的抗滑桩加固稳定性分析[J]. 水利与建筑工程学报, 2015, 13(6): 156-160. FANG Jian, DENG Qin. Stability analysis of reinforced anti-slide piles in bedding slopes with weak interlayers[J]. Journal of Water Resources and Architectural Engineering, 2015, 13(6): 156-160. [19] 许宝田,钱七虎,阎长虹,等.多层软弱夹层边坡岩体稳定性及加固分析[J].岩石力学与工程学报,2009,28(增刊2):3959-3964. XU Baotian, QIAN Qihu, YAN Changhong, et al. Stability and strengthening analyses of slope rock mass containing multi-weak interlayers[J].Chinese Journal of Rock Mechanics and Engineering, 2009, 28(Suppl.2): 3959-3964. [20] 李连祥,张永磊,扈学波.基于PLAXIS 3D有限元软件的某坑中坑开挖影响分析[J].地下空间与工程学报,2016,12(增刊1):254-261. LI Lianxiang, ZHANG Yonglei, HU Xuebo. Finite Element Analysis of A Pit-in-pit Excavation based on PLAXIS 3D [J]. Chinese Journal of Underground Space and Engineering, 2016, 12(Suppl.1): 254-261. [21] 刘国彬, 王卫东. 基坑工程手册[M]. 2版. 北京: 中国建筑工业出版社, 2009.
2024, Vol. 6 
