Limit analysis of slope stability supported by framed prestressed anchor rods
-
摘要: 框架预应力锚杆在边坡工程中应用广泛。在考虑支护结构、锚杆对土体边坡稳定性影响的情况下,基于塑性力学极限分析上限理论的基本原理,推导了其支护边坡的安全系数计算公式。并采用Matlab语言编制算法对推导公式进行全局最优解搜索。对算例采用Flac3d模拟求解其安全系数,和用上限法求得的结果相近。最后采用正交试验设计方法讨论在框架预应力锚杆支护边坡中坡角、坡高、土体性质等内在因素对其稳定性的影响,得出对框架预应力锚杆支护边坡的稳定性影响最大的是坡角,然后再依次为内摩擦角和坡高、黏聚力、坡底支护结构推力设计值、重度,且坡角和内摩擦角对边坡稳定性影响高度显著。Abstract: Framed prestressed anchor rods are widely used in slope engineering.Considering the influences of supporting structures and anchor rods on the stability of soil slopes, the basic principles of the upper limit theory are analyzed, and the formula for calculating the safety factor of supported slope is deduced on the basis of plastic mechanics limit.The algorithm based on Matlab language is adopted to search the global optimal solution.Finally, according to the orthogonal design method, the influences of the internal factors such as slope angle, slope height and soil properties on the stability of prestressed anchor supported slope are discussed.It is concluded that the slope angle has the greatest influences on the stability of the prestressed anchor supported slope, following by the internal friction angle and slope hight, cohesion force, design value of thrust of supporting structures for the slope and soil weight, and the slope height, internal friction angle and slope angle have significant influences on its stability.
-
Keywords:
- slope engineering /
- framed prestressed rod /
- stability /
- limit analysis
-
-
表 1 不同极限平衡法所求的安全系数值
Table 1 Values of safety factor calculated by different limit equilibrium methods
Janbu Morgensternprice Spencer Bishop Janbu Generalized 1.270 1.379 1.378 1.380 1.353 表 2 关于边坡黏聚力、内摩擦角等的因素水平
Table 2 Factors related to slope cohesion, internal friction angle, soil weight, slope angle, slope height and design value of thrust of supporting structures for slope
水平 黏聚力/kPa 内摩擦角/(°) 重度/(kN·m-3) 坡角/(°) 坡高/m 底部支护结构推力设计值/(kN·m-1) 1 18 20 12 30 6 10 2 21 23 14 40 8 30 3 24 26 16 50 10 50 4 27 29 18 60 12 70 5 30 32 20 70 14 90 表 3 正交设计组合情况
Table 3 Combined situations of orthogonal design
试验号 黏聚力/kPa 内摩擦角/(°) 重度/(kN·m-3) 坡角/(°) 坡高/m 底部推力设计值/(kN·m-1) 试验结果 1 18 20 12 30 6 10 1.2240 2 18 23 14 40 8 30 1.2250 3 18 26 16 50 10 50 1.1517 4 18 29 18 60 12 70 1.0310 5 18 32 20 70 14 90 0.9062 6 21 20 14 50 12 90 0.9322 7 21 23 16 60 14 10 0.7520 8 21 26 18 70 6 30 1.1593 9 21 29 20 30 8 50 1.7832 10 21 32 12 40 10 70 1.7141 11 23 20 16 70 8 70 0.8876 12 23 23 18 30 10 90 1.4269 13 23 26 20 40 12 10 1.1765 14 23 29 12 50 14 30 1.1735 15 23 32 14 60 6 50 1.7726 16 27 20 18 40 14 50 0.9716 17 27 23 20 50 6 70 1.4204 18 27 26 12 60 8 90 1.4562 19 27 29 14 70 10 10 1.0271 20 27 32 16 30 12 30 1.8385 21 30 20 20 60 10 30 0.8457 22 30 23 12 70 12 50 0.8671 23 30 26 14 30 14 70 1.5460 24 30 29 16 40 6 90 2.0201 25 30 32 18 50 8 10 1.5728 表 4 正交设计结果
Table 4 Values of orthogonal design
因素 K1 K2 K3 K4 K5 R 黏聚力 1.1076 1.2682 1.2874 1.3428 1.3703 0.2628 内摩擦角 0.9722 1.1383 1.2979 1.407 1.5608 0.5886 重度 1.287 1.3006 1.33 1.2323 1.2264 0.1036 坡角 1.5637 1.4215 1.2501 1.1715 0.9695 0.5943 坡高 1.5193 1.385 1.2331 1.1691 1.0699 0.4494 底部推力设计值 1.1505 1.2484 1.3092 1.3198 1.3483 0.1978 表 5 各个因素显著性分析
Table 5 Significance analysis of various factors
变异来源 偏差平方和 自由度 方差 F值 Fa 显著水平 黏聚力 0.210 4 0.053 5.177 显著 内摩擦角 1.049 4 0.262 25.864 F0.01(4,4)=15.977 极为显著 坡角 1.048 4 0.262 25.829 F0.05(4,4)=6.388 高度显著 坡高 0.636 4 0.159 15.674 F0.1(4,4)=4.107 显著 推力设计值 0.123 4 0.031 3.033 F0.25(4,4)=2.064 有一定影响 误差e 0.041 4 0.010 总和 3.107 -
[1] 周勇, 朱彦鹏. 框架预应力锚杆边坡支护结构的稳定性分析方法及其应用[J]. 工程地质学报, 2008, 16(3): 89-95. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ200803016.htm ZHOU Yong, ZHU Yan-peng. Stability analysis method for prestressed anchor and grillage supporting structures and its application[J]. Journal of Engineering Geology, 2008, 16(3): 89-95. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ200803016.htm
[2] 李忠, 朱彦鹏. 框架预应力锚杆边坡支护结构稳定性计算方法及其应用[J]. 岩石力学与工程学报, 2005, 24(21): 3922-3926. doi: 10.3321/j.issn:1000-6915.2005.21.018 LI Zhong, ZHU Yan-peng, Stability calculation methodsforgrillagesupportingstructurewith prestressed anchor and its application[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(21): 3922-3926. (in Chinese) doi: 10.3321/j.issn:1000-6915.2005.21.018
[3] 龚晓南. 土塑性力学[M]. 杭州: 浙江大学出版社, 1990. GONG Xiao-nan. Soil Plastic Mechanics[M]. Hangzhou: Zhejiang University Press, 1990. (in Chinese)
[4] 董倩, 刘东燕. 均质边坡稳定分析的上限解探讨[J]. 公路交通科技, 2007, 24(6): 8-11. doi: 10.3969/j.issn.1002-0268.2007.06.002 DONG Qian, LIU Dong-yan. Discussionontheupper-boundsolutionof homogeneous soil slope stability[J]. Journal of Highway and Transportation Research and Development, 2007, 24(6): 8-11. (in Chinese) doi: 10.3969/j.issn.1002-0268.2007.06.002
[5] 方薇, 杨果林, 刘晓红, 等. 非均质边坡稳定性极限分析上限法[J]. 中国铁道科学, 2010, 31(6): 14-20. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGTK201006004.htm FANG Wei, YANG Guo-lin, LIU Xiao-hong, et al. The upper-bound limit analysis of the inhomogeneous slope stability[J]. China Railway Science, 2010, 31(6): 14-20. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZGTK201006004.htm
[6] 周强. 利用上限定理的二级边坡地震稳定性研究[J]. 公路工程, 2013, 38(2): 174-176. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGL201302044.htm ZHOU Qiang. Slope with multi-step stability under earthquake forces based on limit analysis[J]. Highway Engineering, 2008, 38(2): 174-176. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGL201302044.htm
[7] 李新坡, 何思明, 徐骏, 等. 预应力锚索加固土质边坡的稳定性极限分析[J]. 四川大学学报(工程科学版), 2006, 38(5): 82-85. https://www.cnki.com.cn/Article/CJFDTOTAL-SCLH200605012.htm LI Xin-po, HE Si-ming, XU Jun, et al. Stability analysis of slopes reinforced with pre-tensioned cables by limit analysis method[J]. Journal of Sichuan University(Engineering Science Edition), 2006, 38(5): 82-85. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SCLH200605012.htm
[8] 王根龙, 伍法权, 祁生文, 等. 加锚岩质边坡稳定性评价的极限分析上限法研究[J]. 岩石力学与工程学报, 2007, 26(12): 2556-2563. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200712025.htm WANG Gen-long, WU Fa-quan, QI Sheng-wen, et al. Research on limit analysis upper bound method for stability evaluation of anchored rock slop[J]. Chinese Journal of Rock Mechanics and Engineering, 2007, 26(12): 2556-2563. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200712025.htm
[9] BISHOP A W. The use of the slip circle in the stability analysis of slopes[J]. Géotechnique, 1955, 5(1): 7-17.
[10] ZIENKIEWICZ O C, HUMPHESON C, LEWIS R W. Associated and non-associated visco-plasticity and plasticity in soil mechanics[J]. Géotechnique, 1975, 25(4): 671-689.
[11] DUNCAN J M. State of the art: limit equilibrium and finite element analysis of slopes[J]. Journal of Geotechnical Engineering, 1996, 122(7): 577-596.
[12] 郑颖人, 陈祖煜, 王恭先, 等. 边坡与滑坡工程治理[M]. 北京: 人民交通出版社, 2007. ZHENG Ying-ren, CHEN Zu-yu, WANG Gong-xian, et al. Slope and Landslide Engineering Treatment[M]. Beijing: China Communications Press, 2007. (in Chinese)
[13] SOUBRA A H, MACUH B. Active and passive earth pressure coefficients by a kinematical approach[J]. Geotechnical Engineering, 2002, 155(2): 119-131.
[14] CHEN W F. Limit Analysis and Soil Plasticity[M]. New York: Elsevier Scientific Publishing Co, 1975.
[15] 陈祖煜. 土力学经典问题的极限分析上、下限解[J]. 岩土工程学报, 2002, 24(1): 1-11. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200201000.htm CHEN Zu-yu. Limit analysis for the classic problems of soil mechanics[J]. Chinese Journal of Geotechnical Engineering, 2002, 24(1): 1-11. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC200201000.htm
[16] 杨昕光, 周密, 张伟, 等. 基于二阶锥规划的边坡稳定上限有限元分析[J]. 长江科学院院报, 2016, 33(12): 61-67. https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB201612013.htm YANG Xin-guang, ZHOU Mi, ZHANG Wei, et al. Upper bound finite element analysis of slope stability using second-order cone programming[J]. Journal of Yangtze River Scientific Research Institute, 2016, 33(12): 61-67. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB201612013.htm
[17] 赵炼恒, 罗强, 李亮, 等. 基于失稳状态耗能最小原理的预应力锚索加固边坡稳定性上限解析[J]. 岩土力学, 2013, 34(2): 426-432. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201302020.htm ZHAO Lian-heng, LUO Qiang, LI Liang, et al. Energy analysis method for slopes reinforcing with prestressed anchor cables based on minimum energy principle of instability state[J]. Rock and Soil Mechanics, 2013, 34(2): 426-432. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201302020.htm
[18] 夏世友, 张电吉, 夏亮, 等. 有限差分强度折减法求解边坡安全系数[J]. 武汉工程大学学报, 2012, 34(4): 19-21, 26. https://www.cnki.com.cn/Article/CJFDTOTAL-WHHG201204006.htm XIA Shi-you, ZHANG Dian-ji, XIA Liang, et al. Strength reduction finite difference method for solving safety factor of slope[J]. Journal of Wuhan Institute of Technology, 2012, 34(4): 19-21, 26. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-WHHG201204006.htm
[19] LUAN Mao-tian, WU Ya-jun, NIAN Ting-kai. A criterion for evaluating slope stability based on development of plastic zone by shear strength reduction FEM[J]. Journal of Seismology, 2003, 23(3): 1-8.