笔者使用Taron等提出的颗粒聚集体的压力溶解模型和摩尔-库伦准则,假设在饱和的石英颗粒聚集岩体中有一实验室尺度的高放废物地质处置库模型,针对其拟定两种计算工况:(1)内摩擦角和黏聚力均为常数;(2)内摩擦角为常数,黏聚力是孔隙率的负指数函数,进行4a处置时段的热-水-应力(THM)耦合有限元数值模拟,就岩体中的温度场、渗流场、应力场和浓度场的变化及分布情况进行了考察。结果显示:与黏聚力是常数的情况相比,黏聚力随孔隙率而变化时,岩体相同部位进入屈服阶段的时机滞后,塑性区减小,并推迟了塑性部位的溶质浓度、迁移/沉淀质量、反应体积和颗粒贯穿深度的突变时间;弹塑性分析中由于应力调整和增大了分子扩散系数,使得塑性区的颗粒介质的溶解、迁移和沉淀相比于弹性区有明显的变化,并对渗流场(孔隙水的压力及流速)和应力场产生显著的影响。
Abstract
The model of pressure solution for granular aggregates established by Taron was introduced into the FEM code for analysis of T-H-M coupling in porous media and the Mohr-Coulomb yield criterion was used. Aiming at a model of hypothetical nuclear waste repository in a saturated quartz aggregate rock mass with a laboratory scale, two computation cases were designed: (1) both of the internal friction angle and cohesion are constants; (2) the internal friction angle is constant, but the cohesion is a negative exponent function of porosity, then the corresponding numerical simulations for a disposal period of 4 years were carried out, and the states of temperatures, solute concentrations in the intergranular fluid film and at the pore space, removal and precipitation masses, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass were investigated. The results show:compared with the case of constant cohesion, when the cohesion changes with the porosity, the time at which the same parts of rock mass entering yield state delays, the plastic zone decreases, and the times of causing sudden change of solute concentrations, removal/precipitated masses, cumulative granular interpenetrations and reaction volumes are postponed. Because of the stress adjustment and the increasing molecular diffusivity in the elasto-plastic analysis, there are obvious changes of solution, transfer and precipitation of aggregate medium in the plastic zones, and the seepage field(including pressures and flow velocities of pore water) and the stress field are markedly influenced by these changes.
关键词
压力溶解 /
孔隙率 /
弹塑性模型 /
热-水-应力耦合 /
有限元分析
{{custom_keyword}} /
Key words
pressure solution /
porosity /
elasto-plastic model /
thermo-hydro-mechanical coupling /
FEM analysis
{{custom_keyword}} /
中图分类号：
TU452
{{custom_clc.code}}
({{custom_clc.text}})
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 王迎春, 陈剑. 红层软岩微观结构与抗剪强度关系实验分析[J]. 现代地质, 2013, 27(3): 738-742. (Wang Yingchun, Chen Jian. Preliminary research on the relationship between microscopic structure and shear strength of red- bed soft rocks [J]. Geoscience, 2013, 27(3): 738-742. (in Chinese))
[2] 黄英, 张祖莲, 金克盛. 昆明击实红土的抗剪强度特性研究[J]. 昆明理工大学学报(自然科学版), 2014, 39(1): 33-39. (Huang Ying, Zhang Zulian, Jin Kesheng. Research of shear strength characteristics of compacted Kunming laterite [J]. Journal of Kunming University of Science and Technology (Natural Science Edition), 2014, 39(1): 33-39. (in Chinese))
[3] 李鹏, 刘建, 李国和, 等. 水化学作用对砂岩抗剪强度特性影响效应研究[J]. 岩土力学, 2011, 32(2): 380-386. (Li Peng, Liu Jian, Li Guohe, et al. Experimental study for shear strength characteristics of sandstone under water-rock interaction effects [J]. Rock and Soil Mechanics, 2011, 32(2): 380-386. (in Chinese))
[4] 杨海博, 武云云. 致密储层岩石的微观结构和力学性质试验分析[J]. 复杂油气藏, 2011, 4(3): 10-15. (Yang Haibo, Wu Yunyun. The experimental analysis of microstructure and mechanical properties of tight reservoir rocks [J]. Complex Hydrocarbon Reservoirs, 2011, 4(3): 10-15. (in Chinese))
[5] 谢新生, 汤巍, 王锦叶. 多孔生态混凝土强度与孔隙率的试验研究[J]. 四川大学学报(工程科学版), 2008, 40(6): 19-23. (Xie Xinsheng, Tang Wei, Wang Jinye. Experimental study on strength and porosity ratio of porous ecological concrete [J]. Journal of Sichuan University (Engineering Science Edition), 2008, 40(6): 19-23. (in Chinese))
[6] 杨永明, 鞠杨, 刘红彬, 等.孔隙结构特征及其对岩石力学性能的影响[J]. 岩石力学与工程学报, 2009, 28(10): 2031-2038. (Yang Yongming, Ju Yang, Liu Hongbin, et al. Influence of porous structure properties on mechanical performances of rock [J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(10):2031-2038. (in Chinese))
[7] Zheng B, Elsworth D. Strength evolution in heterogeneous granular aggregates during chemo–mechanical compaction [J]. International Journal of Rock Mechanics & Mining Sciences, 2013, 60(6): 217-226
[8] Taron J, Elsworth D. Constraints on compaction rate and equilibrium in the pressure solution creep of quartz aggregates and fractures: Controls of aqueous concentration [J]. Journal of Geophysical Research, 2010, 115(B7):1115-1127.
[9] Lee D S. Elsworth D, Yasuhara H, et al. Experiment and modeling to evaluate the effects of proppant-pack diagenesis on fracture treatments[J], Journal of Petroleum Science and Engineering,2006, 74(1): 67-76
[10]Owen D, Hinton E. Finite elements in plasticity: theory and practice[M]. Pineridge Press Ltd. U.K, 1980.
[11]张玉军. 废料地质处置近场热-水-应力-迁移耦合二维有限元分析[J].岩土工程学报, 2007, 29(10):1553-1557. (Zhang Yujun. 2D FEM analysis for coupled thermo-hydro-mechanical-migratory process in near field of geological disposal of nuclear waste[J]. Chinese Jounal of Geotechnical Engineering, 2007, 29(10): 1553-1557 (in Chinese))
[12]张玉军, 杨朝帅, 徐刚. 压力溶解对颗粒聚集岩体中热-水-应力耦合影响的数值模拟[J].岩土力学, 2014, 35(5):1461-1469. (Zhang Yujun, Yang Chaoshuai, Xu Gang. Numerical simulation for influences of pressure solution on thermo-hydro-mechanical coupling in granule aggregate rock[J]. Rock and Soil Mechanics, 2014, 35(5): 1461-1469. (in Chinese))
[13]Yasuhare H, Elsworth D, Polak A. A mechanistic model for compaction of granular aggregates moderated by pressure solution [J]. Journal of Geophysical Research Soild Earth, 2003, 108(B11):34-37.
[14]Chijimatsu M, Kurikami H, Ito A, et al. Implication of THM coupling on the near-field of a nuclear waste repository in a homogeneous rock mass [R]. Decovales III-Task3-Bench Mark Test 1(BMT1)-Subtask BMT1-B, 2002:1-43
[15]Rutqvist J, Chijimatsu M, Jing L, et al. A numerical study of THM effects on the near-field safety of a hypothetical nuclear waste repository—BMT1 of the Decovalex III project. Part 3: Effects of THM coupling in sparsely fractured rocks [J]. International Journal of Rock Mechanics and Mining Sciences, 2005, 42(5/6):745-755.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
基金
国家重点基础研究发展计划(973)资助项目(2010CB732101);国家自然科学基金(51379201)
{{custom_fund}}
PDF(2140 KB)
