Simplified method for nonlinear settlement calculation in soft soils considering lateral deformation
YANG Guang-hua1, 2, 3, HUANG Zhi-xing2, LI Zi-yun2, JIANG Yan1, 3, LI De-ji1
1. Guangdong Research Institute of Water Resources and Hydropower, Guangzhou 510610, China; 2. School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510641, China; 3. Geotechnical Engineering Technology Center of Guangdong Province, Guangzhou 510610, China
Abstract：The common method for computing settlement of soft soils is the layer-wise summation method using compression modulus under the confined condition. But the lateral deformation makes a large part of the whole settlement. To eliminate the calculation error, the method in the national specifications or codes is that the results are multiplied by an empirical coefficient from 1.1 to 1.7. Since the empirical coefficient is not sure, a new method considering the lateral deformation is proposed. This method divides the settlement of soft soil into two parts. One is the settlement Sc caused by 1 D confined compression using the layer-wise summation and e-p curve to compute, the other is the settlement Sd caused by lateral deformation using the same way but the parameter is secant modulus Ep from the e-p curve and Duncan-Chang model. So the e-p curve is the core for computing the settlement. In practical engineering, the initial void ratio e0 and compression modulus Es1-2 are frequently used and can reflect the characteristics of the soils well. The two parameters are combined with compression index Cc, thus we can use e-lgp curve to get the compression modulus Esi under different stress states. Since Esi, Sc, Sd are easy to get, it brings a big convenience to engineering computation. Finally, the applicability of the proposed method is validated through an engineering case.
[1] 杨光华. 软土地基非线性沉降计算的简化法[J]. 广东水利水电, 2001(1): 3-5. (YANG Guang-hua. A simplified calculation method for soft ground nonlinear settlement[J]. Guangdong Water Resources and Hydropower, 2001(1): 3-5. (in Chinese)) [2] 杨光华, 李德吉, 李思平, 等. 计算软土地基非线性沉降的一个简化方法[C]// 第九届土力学及岩土工程学术会议论文集. 北京, 2003: 506-510. (YANG Guang-hua, LI De-ji, LI Si-ping, et al. A simplified method for calculatingnonlinear settlement of soft ground[C]// Ninth Soil Mechanics and Geotechnical Engineering Conference Proceedings. Beijing, 2003: 506-510. (in Chinese)) [3] 王志亮, 李永池, 殷宗泽. 考虑土体侧胀性的路堤沉降计算探讨[J]. 岩石力学与工程学报, 2005, 24(10): 1772-1777. (WANG Zhi-liang, LI Yong-chi, YIN Zong-ze. Discussion on settlement calculation of embankment considering lateral dilation behavior of soils[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(10): 1772-1777. (in Chinese)) [4] JGJ79—2012 建筑地基处理技术规范[S]. 2012. (JGJ79—2012 Technical code for ground treatment of buildings[S]. 2012. (in Chinese)) [5] JTJ017—96 公路软土地基路堤设计与施工技术规范[S]. 1996. (JTJ017—96 Technical specification for design andconstruction of highway embankment on soft ground[S]. 1996. (in Chinese)) [6] GB50286—98 堤防工程设计规范规范[S]. 1998. (GB50286—98 Code for design of levee project[S]. 1998. (in Chinese)) [7] GB50007—2011 建筑地基基础设计规范[S]. 2012. (GB50007—2011 Code for design of building foundation[S]. 2012. (in Chinese)) [8] 杨光华, 姚丽娜. 基于 e - p 曲线的软土地基非线性沉降的实用计算方法[J]. 岩土工程学报, 2015(2): 242-249. (YANG Guang-hua, YANG Guang-hua. Practical method for calculating nonlinear settlement of soft ground based on e-p curve[J]. Chinese Journal of Geotechnical Engineering, 2015(2): 242-249. (in Chinese)) [9] 姚丽娜. 基于 e - p 曲线的软土地基非线性沉降实用计算方法研究[D]. 广州: 华南理工大学, 2014. (YANG Guang-hua. Practical method for calculating nonlinear settlement of soft ground based on e - p curve[D]. Guangzhou: South China University of Technology, 2014. (in Chinese)) [10] 彭长学, 杨光华. 软土 e - p 曲线确定的简化方法及在非线性沉降计算中的应用[J]. 岩土力学, 2008(6): 1706-1710. (PENG Chang-xue, YANG Guang-hua. A simplified method for determining e - p curve of soft soil and its application to analyzing nonlinear settlement of foundation[J]. Rock and Soil Mechanics, 2008(6): 1706-1710. (in Chinese)) [11] 李广信. 高等土力学[M]. 北京: 李广信, 2014: 21-26. (LI Guang-xin. Advanced soil mechanics[M]. Beijing:Tsinghua University Press, 2004: 21-26. (in Chinese)) [12] 刘成宇. 土力学[M]. 北京: 中国铁道出版社, 2005. (LIU Cheng-yu. Soil mechanics[M]. Beijing: China Railway Press, 1990. (in Chinese)) [13] 杨小平. 土力学[M]. 广州: 华南理工大学出版社, 2001. (YANG Xiao-ping. Advanced soil mechanics[M]. Guangzhou: South China University of Technology Press, 2001. (in Chinese)) [14] 陆培炎, 熊丽珍, 陈韶永, 等. 软土上一个土堤试验分析[M]. 北京: 科学出版社, 2006: 121-143. (LU Pei-yan, XIONG Li-zhen, CHEN Shao-yong, et al. A trial embankment analysis on soft soil[M]. Beijing: Science Press, 2006: 121-143. (in Chinese))
