|
|
|
| A PHYSICAL MODELING STUDY OF WATER FLOW AND HEAT TRANSFER IN UN-FILLED FRACTURED ROCKS |
| LU Wei，XIANG Yanyong，LI Tao |
| (School of Civil Engineering，Beijing Jiaotong University，Beijing 100044，China) |
|
|
|
|
Abstract The characteristics of water flow and heat transfer in fractured rocks is an important component for the performance and safety evaluation of high-level radioactive nuclear waste repositories. A meter-scale physical modelling experiment is conducted to study the behaviour of flow and heat transfer in multi-fractured rocks with variable heat source temperature and water flow velocity. The granite rocks are taken from the Beishan area in Gansu province，which is being investigated as potential site for the high-nuclear waste repository in China. The fractured rock model of 150.25 cm×90.4 cm×30 cm(height×width×thickness) consists of 18 granite rocks with 2 vertical fractures and 2 horizontal fractures；a heater is placed on one side of the fractured rock model and thermal sensors and pressure sensors are installed in the interior. The experimental results reveal that：(1) since there exists a distance between the heat source and the vertical fractures，heat conduction and fracture water flow are not significantly coupled until after one hour of the experiment；(2) at the junction of vertical and horizontal fractures，due to local heat convection，the temperature of water in the vicinity is significantly increased；(3) the range of influence of the heat source is larger，and the time for asymptotically approaching steady-state is longer，for higher heat source temperatures and lower water velocities in the fractures；(4) vertical fracture adjacent to the heat source controls the temperature distribution in the model，and the horizontal fractures may increase the range of influence of the heat source；(5) under the given conditions，with the vertical fracture water temperatures well below 100 ℃，there is little effect on the water pressure.
|
|
Received: 10 September 2010
|
|
|
|
| [1] 郭永海，王 驹. 高放废物地质处置中的地质、水文、地质、地球化学关键科学问题[J]. 岩石力学与工程学报，2007，12(增2)：3 924–3 931.(GUO Yonghai，WANG Ju. Key scientific issues of geology，hydrogeology and geochemistry in high-level radioactive waste geological disposal[J]. Chinese Journal of Rock Mechanics and Engineering，2007，12(Supp.2)：3 924–3 931.(in Chinese))
[2] 杨春和，王贵宾，王 驹，等. 甘肃北山预选区岩体力学与渗流特性研究[J]. 岩石力学与工程学报，2006，25(4)：825–832.(YANG Chunhe，WANG Guibin，WANG Ju，et al. Study on rock mass mechanics and seepage characteristics of candidate site-Beishan，Gansu Province[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(4)：825–832.(in Chinese))
[3] 刘月妙，王 驹，谭国焕，等. 高放废物处置北山预选区深部完整岩石基本物理力学性能及时温效应[J]. 岩石力学与工程学报，2007，26(10)：2 034–2 042.(LIU Yuemiao，WANG Ju，TAN Guohuan，et al. Basic physico-mechanical properties and time-temperature effect of deep intact rock from Beishan preselected area for high-level radioactive waste disposal[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(10)：2 034–2 042.(in Chinese))
[4] 郭永海，王 驹，王志明，等. 高放废物处置库甘肃北山预选区地下水位动态特征[J]. 铀矿地质，2010，26(1)：46–50.(GUO Yonghai，WANG Ju，WANG Zhiming，et al. Dynamic characteristic of underground water table in Beishan pres-election area of high-level radioactive waste disposal repository[J]. Uranium Geology，2010，26(1)：46–50.(in Chinese))
[5] TSANG C F，STEPHANSSON O，JING L，et al. DECOVALEX project：from 1992 to 2007[J]. Environmental Geology，2009，57(6)：1 221–1 237.
[6] CHAN T，KHAIR K，JING L，et al. International comparison of coupled thermo-hydro-mechanical models of a multiple-fracture bench mark problem：DECOVALEX phase I，bench mark test 2[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1995，32(5)：435–452.
[7] TSANG C F，JING L，STEPHANSSON O，et al. The DECOVALEX III project：a summary of activities and lessons learned[J]. International Journal of Rock Mechanics and Mining Sciences，2005，42(5/6)：593–610.
[8] CHIJIMASTSU M，FUJITA T，SUGITA Y，et al. Field experiment，results and THM behaviour in the Kamaishi mine experiment[J]. International Journal for Numerical and Analytical Methods in Geomechanics，2001，38(1)：67–68.
[9] ALONSO E E，ALCOVERRO J，COSTE F，et al. The FEBEX benchmark test：case definition and comparison of modeling approaches[J]. International Journal of Rock Mechanics and Mining Sciences，2005，42(5/6)：611–638.
[10] LIU Q S，ZHANG C Y，LIU X Y. Numerical modeling and simulation of coupled THM processes in Task_D of DECOVALEX_IV[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(4)：709–720.
[11] 柴军瑞，韩柱群，仵彦卿. 岩体一维渗流场与温度场耦合模型的解析演算[J]. 地下水，1999，21(4)：180–182.(CHAI Junrui，HAN Zhuqun，WU Yanqing. Checking computations on one-dimensional coupling model coupling temperature-seepage in rock mass[J]. Groundwater，1999，21(4)：180–182.(in Chinese))
[12] 赵 坚. 岩石裂隙中的水流–岩石热传导[J]. 岩石力学与工程学报，1999，18(2)：119–123.(ZHAO Jian. Experimental study of flow-rock heat transfer in rock fractures[J]. Chinese Journal of Rock Mechanics and Engineering，1999，18(2)：119–123.(in Chinese))
[13] 蒋中明，DASHNOR H. 核废料贮存库围岩体热响应耦合场研究[J]. 岩土工程学报，2006，28(8)：953–956.(JIANG Zhongming，DASHNOR H. Studies on coupled field of thermal response in rock mass of nuclear waste repository[J]. Chinese Journal of Geotechnical Engineering，2006，28(8)：953–956.(in Chinese))
[14] 陈益峰，周创兵，童富果，等. 多相流传输THM全耦合数值模拟及程序验证[J]. 岩石力学与工程学报，2009，28(4)：649–665.(CHENG Yifeng，ZHOU Chuangbing，TONG Fuguo，et al. A numerical model for fully coupled THM processes with multiphase flow and code validation[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(4)：649–665.(in Chinese))
[15] 刘文岗，王 驹，周宏伟，等. 高放废物处置库花岗岩热–力耦合模拟研究[J]. 岩石力学与工程学报，2009，28(增1)：2 875– 2 883.(LIU Wengang，WANG Ju，ZHOU Hongwei，et al. Coupled thermo-mechanical analysis of granite for high-level radioactive waste repository[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(Supp.1)：2 875–2 883.(in Chinese))
[16] 张玉军. 核废物地质处置中热–水–应力耦合对迁移影响的三维有限元模拟[J]. 岩土力学，2009，30(7)：2 126–2 132.(ZHANG Yujun. 3D finite element simulation for influence of thermo-hydro- mechanical coupling on migration in geological disposal of nuclear waste[J]. Rock and Soil Mechanics，2009，30(7)：2 126–2 132.(in Chinese)) |
|
|
|
2011, Vol. 30 
