|
|
|
| BACK ANALYSIS OF ROCK PERMEABILITY WITH CONSIDERATION OF TRANSIENT FLOW PROCESS |
| LIU Wu1，2，CHEN Yifeng1，2，HU Ran1，2，ZHOU Chuangbing1，2 |
(1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan，Hubei 430072，
China；2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering，Ministry of Education，Wuhan University，
Wuhan，Hubei 430072，China) |
|
|
|
|
Abstract A new approach for back analysis the rock/soil permeability based on the transient flow was developed considering the transient nature of the seepage flow in rocks and soils during construction and operation of engineering works. The proposed method utilizes the measured transient data of both piezometric head and flow rate is based on the orthogonal design，the finite element analysis of transient seepage flow，the BP(back propagation) neural network and the genetic algorithm. In order to avoid the dimensional inconsistency induced by different types of measurements，normalized error terms of the transient pressure head and seepage flow rate are used for constructing the objective function，and a weight coefficient w is introduced to balance the contributions by the piezometric head and flow rate terms. The proposed method is applied to back calculate the hydraulic conductivity around the foundation pit for construction of the rockfill dam with gravel wall core on Changhe river. The measured water leakage is much higher than the one expected in the design period. The back-calculated piezometric head and flow rate are in good agreement with the measured results. The back-calculated hydraulic conductivities of the foundation rocks are strictly within the ranges of permeability of graded rock mass determined with the in site borehole packer tests，which demonstrates the effectiveness of the back-analysis method and the reliability of the back-calculated results.
|
|
Received: 20 January 2014
|
|
|
|
| [1] 陈益峰，周创兵，盛永清. 应变敏感的裂隙及裂隙岩体水力传导特性研究[J]. 岩石力学与工程学报，2006，25(12)：2 441–2 452. (CHEN Yifeng，ZHOU Chuangbing，SHENG Yongqing. Strain- dependent hydraulic conductivity for single rock fracture and fractured rock mass[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(12)：2 441–2 452.(in Chinese))
[2] ZHOU C S，LI K F，PANG X Y. Effect of crack density and connectivity on the permeability of microcracked solids[J]. Mechanics of Materials，2011，43(12)：969–978.
[3] 刘建刚，陈建生. 基岩渗漏成因病险堤坝的两个典型实例[J]. 岩石力学与工程学报，2003，22(4)：683–688.(LIU Jiangang，CHEN Jiansheng. Two typical examples of dykes with defects or in danger resulted from bed rock permeation[J]. Chinese Journal of Rock Mechanics and Engineering，2003，22(4)：683–688.(in Chinese))
[4] 刘建刚，陈建生，陈 亮，等. 小浪底缓倾角结构坝基的渗漏及示踪探测研究[J]. 岩石力学与工程学报，2004，23(8)：1 339–1 343. (LIU Jiangang，CHEN Jiansheng，CHEN Liang，et al. Study of seepage in low-dip bedded structure of Xiaolangdi dam abutment by tracer method[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(8)：1 339–1 343.(in Chinese))
[5] TURKMEN S. Treatment of the seepage problems at the Kalecik dam (Turkey)[J]. Engineering Geology，2003，68(3/4)：159–169.
[6] 景来红，段世超，杨顺群. 渗流反演分析在工程设计中的应用[J]. 岩石力学与工程学报，2007，26(增2)：4 503–4 509.(JING Laihong，DUAN Shichao，YANG Shunqun. Application of seepage back analysis to engineering design[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(Supp.2)：4 503–4 509.(in Chinese))
[7] 钱七虎. 地下工程建设安全面临的挑战与对策[J]. 岩石力学与工程学报，2012，31(10)：1 945–1 956.(QIAN Qihu. Challenges faced by underground projects construction safety and countermeasures[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(10)：1 945–1 956.(in Chinese))
[8] 包腾飞，顾冲时，吴中如. 李家峡大坝6号坝段坝基扬压力异常成因综合分析[J]. 岩土工程学报，2008，30(10)：1 460–1 466.(BAO Tengfei，GU Chongshi，WU Zhongru. Analysis of uplift pressure anomaly of Lijiaxia dam foundation[J]. Chinese Journal of Geotechnical Engineering，2008，30(10)：1 460–1 466.(in Chinese))
[9] 盛金昌，速宝玉，詹美礼. 三维天然渗流场反演分析及工程应用[J]. 岩石力学与工程学报，2003，22(2)：203–207.(SHENG Jinchang，SU Baoyu，ZHAN Meili. Back analysis of 3D seepage problem and its engineering application[J]. Chinese Journal of Rock Mechanics and Engineering，2003，22(2)：203–207.(in Chinese))
[10] 王 媛，刘 杰. 重力坝坝基渗透参数进化反演分析[J]. 岩土工程学报，2003，25(5)：552–556.(WANG Yuan，LIU Jie. Back analysis of the permeability coefficients of gravity dam foundation by evolution method[J]. Chinese Journal of Geotechnical Engineering，2003，25(5)：552–556.(in Chinese))
[11] 李康宏，邓祥辉，何 萌，等. 基于钻孔资料的某尾矿坝渗透系数反演分析有限元模型建立[J]. 岩石力学与工程学报，2004，23(增1)：4 329–4 332.(LI Kanghong，DENG Xianghui，HE Meng，et al. Finite element modeling of back analysis of permeability coefficient of a tailing dam based on boring data[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(Supp.1)：4 329–4 332.(in Chinese))
[12] 祁 涛，张均锋. 某水电站坝址区三维渗流参数反演[J]. 岩石力学与工程学报，2005，24(20)：168–172.(QI Tao，ZHANG Junfeng. Inverse analysis of seepage parameters for dam foundation of a hydropower station[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(20)：168–172.(in Chinese))
[13] 崔皓东，朱岳明. 二滩高拱坝坝基渗流场的反演分析[J]. 岩土力学，2009，30(10)：3 194–3 199.(CUI Haodong，ZHU Yueming. Back analysis of seepage field of Ertan high arch dam foundation[J]. Rock and Soil Mechanics，2009，30(10)：3 194–3 199.(in Chinese))
[14] 陈益峰，周创兵. 隔河岩坝基岩体在运行期的弹塑性力学参数反演[J]. 岩石力学与工程学报，2002，21(7)：968–975.(CHEN Yifeng，ZHOU Chuangbing. Back analysis on elasto-plastic mechanic parameters of rock foundation of Geheyan dam during running period[J]. Chinese Journal of Rock Mechanics and Engineering，2002，21(7)：968–975.(in Chinese))
[15] 陈益峰，周创兵. 基于正交设计的复杂坝基弹塑性力学参数反演[J]. 岩土力学，2002，23(4)：450–454.(CHEN Yifeng，ZHOU Chuangbing. Back analysis of elastoplastic mechanical parameter of complex dam foundation on the basis of orthogonal experiments[J]. Rock and Soil Mechanics，2002，23(4)：450–454.(in Chinese))
[16] CHEN Y F，HU R，ZHOU C B，et al. A new parabolic variational inequality formulation of Signorini?s condition for non-steady seepage problems with complex seepage control systems[J]. International Journal for Numerical and Analytical Methods in Geomechanics，2011，35(9)：1 034–1 058.
[17] 胡 冉，陈益峰，周创兵，等. 非稳定渗流问题的变分不等式方法及工程应用[J]. 水动力学研究与进展，2011，26(2)：239–251.(HU Ran，CHEN Yifeng，ZHOU Chuangbing，et al. A variational inequality approach for non-steady seepage problems and its application in engineering practices[J]. Chinese Journal of Hydrodynamics，2011，26(2)：239–251.(in Chinese))
[18] 陈益峰，周创兵，毛新莹，等. 水布垭地下厂房围岩渗控效应数值模拟与评价[J]. 岩石力学与工程学报，2010，29(2)：308–318. (CHEN Yifeng，ZHOU Chuangbing，MAO Xinying，et al. Numerical simulation and assessment of seepage control effects on surrounding rocks of underground powerhouse in Shuibuya hydropower project[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(2)：308–318.(in Chinese))
[19] CHEN Y F，HU R，ZHOU C B，et al. A new classification of seepage control mechanisms in geotechnical engineering[J]. Journal of Rock Mechanics and Geotechnical Engineering，2010，2(3)：209–222.
[20] ZHENG H，LIU D F，LEE C F，et al. A new formulation of Signorini's type for seepage problems with free surfaces[J]. International Journal for Numerical Methods in Engineering，2005，64(1)：1–16.
[21] 邰淑彩，孙韫玉，何娟娟. 应用数理统计[M]. 武汉：武汉大学出版社，2005：204–231.(TAI Shucai，SUN Yunyu，HE Juanjuan. Applied mathematical statistics[M]. Wuhan：Wuhan University Press，2005：204–231.(in Chinese))
[22] FENG X T，ZHANG Z Q，SHENG Q. Estimating mechanical rock mass parameters relating to the Three Gorges Project permanent shiplock using an intelligent displacement back analysis method[J]. International Journal of Rock Mechanics and Mining Sciences，2000，37(7)：1 039–1 054.
[23] 毛新莹，潘少华，白正雄. 双江口水电站复杂坝基初始渗流场反分析[J]. 岩土力学，2008，29(增1)：135–139.(MAO Xinying，PAN Shaohua，BAI Zhengxiong. Back analysis of initial seepage field of complex dam foundation at Shuangjiangkou hydropower station[J]. Rock and Soil Mechanics，2008，29(Supp.1)：135–139.(in Chinese))
[24] 张 明，卢裕杰，毕忠伟，等. 利用神经网络的反馈分析方法及其在地下厂房中的应用[J]. 岩石力学与工程学报，2010，29(11)：2 211– 2 220.(ZHANG Ming，LU Yujie，BI Zhongwei，et al. Feedback analysis method using artificial neural network and its application to underground powerhouse[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(11)：2 211–2 220.(in Chinese))
[25] DENG J H，LEE C F. Displacement back analysis for a steep slope at the Three Gorges Project site[J]. International Journal of Rock Mechanics and Mining Sciences，2001，38(2)：259–268.
[26] MONJEZI M，DEHGHANI H. Evaluation of effect of blasting pattern parameters on back break using neural networks[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(8)：1 446– 1 453.
[27] WANG H B，XU W Y，XU R C. Slope stability evaluation using back propagation neural networks[J]. Engineering Geology，2005，80(3/4)：302–315.
[28] 周 喻，吴顺川，焦建津，等. 基于BP神经网络的岩土体细观力学参数研究[J]. 岩土力学，2011，32(12)：3 821–3 826.(ZHOU Yu，WU Shunchuan，JIAO Jianjin，et al. Research on mesomechanical parameters of rock and soil mass based on BP neural network[J]. Rock and Soil Mechanics，2011，32(12)：3 821–3 826.(in Chinese))
[29] 杜 娟，殷坤龙，柴 波. 基于诱发因素响应分析的滑坡位移预测模型研究[J]. 岩石力学与工程学报，2009，28(9)：1 783–1 789.(DU Juan，YIN Kunlong，CHAI Bo. Study of displacement prediction model of landslide based on response analysis of inducing factors[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(9)： 1 783–1 789.(in Chinese))
[30] YU Y Z，ZHANG B Y，YUAN H N. An intelligent displacement back-analysis method for earth-rockfill dams[J]. Computers and Geotechnics，2007，34(6)：423–434.
[31] KURTULUS B，RAZACK M. Evaluation of the ability of an artificial neural network model to simulate the input-output responses of a large karstic aquifer：the La Rochefoucauld aquifer(Charente，France)[J]. Hydrogeology Journal，2007，15(2)：241–254.
[32] RAFIAI H，JAFARI A，MAHMOUDI A. Application of ANN-based failure criteria to rocks under polyaxial stress conditions[J]. International Journal of Rock Mechanics and Mining Sciences，2013，59(1)：42–49.
[33] RAFIAI H，JAFARI A. Arti?cial neural networks as a basis for new generation of rock failure criteria[J]. International Journal of Rock Mechanics and Mining Sciences，2011，48(7)：1 153–1 159.
[34] GOLDBERG D E. Genetic algorithms in search，optimization and machine learning[M]. New York：Addison-Wesley，1989：1–21.
[35] MAJDI A，BEIKI M. Evolving neural network using a genetic algorithm for predicting the deformation modulus of rock masses[J]. International Journal of Rock Mechanics and Mining Sciences，2010，47(2)：246–253.
[36] 方开泰. 均匀设计与均匀设计表[M]. 北京：科学出版社，1994：69–97.(FANG Kaitai. Uniform design and uniform design table[M]. Beijing，Science Press，1994：69–97.(in Chinese)) |
|
|
|
2015, Vol. 34 
