共查询到19条相似文献，搜索用时 156 毫秒
1.
比利时放射性核废料地质备选场址Boom clay是一种典型的横观各向同性材料,在Drucker-Prager帽盖模型的基础上,构建了适用于Boom clay的横观各向同性特点的热-水-力耦合弹塑性本构模型,该模型可反映温度对其强度、弹性模量、渗透性等的影响,并在ABAQUS中进行了二次开发。为验证所建立模型的合理性,结合比利时HADES地下实验室ATLAS Ⅲ现场加热试验结果,应用所提出的模型对加热过程中围岩的温度和孔隙水压力的变化规律进行了数值仿真分析。结果表明:所建立的模型能够正确地描述现场加热试验过程中围岩温度场和孔压场所呈现出的各向异性特征,主要表现为热源水平面内测点的孔压在加热功率升高时先略为下降后才升高,在加热功率下降时先略为升高后才下降,而竖直面内测点的孔压在加热功率升高时立即升高,在加热功率下降时立即下降。研究成果表明,考虑各向异性的THM耦合分析能更好地反映加热过程中泥岩温度场和孔压场的实际分布情况,研究结果对类似工程或现场试验的设计、安全运行提供重要的决策依据。 相似文献
2.
黏土的热-力耦合本构模型研究在许多工程领域,尤其是核废料地下处置方面有着十分重要的工程意义。根据Boom黏土的在不同温度下的三轴与固结试验的结果,综合考虑了温度对黏土的强度与弹性模量的影响,在Drucker-Prager(简称D-P)帽盖模型的基础上,引入了硬化方程和热损伤、力学损伤的演化方程,建立了适用于黏土的热-力耦合弹塑性损伤本构模型。将模型在ABAQUS中进行了二次开发,根据试验结果反演得到了Boom黏土的模型参数。利用所建立的本构模型,对比利时HADES试验室中的ATLAS III现场试验进行了数值仿真,计算结果表明,模型的计算结果与现场实测的结果能较好地吻合,证明了模型的合理性。 相似文献
3.
高放废物地质处置岩体材料选取中,黏土岩因具有低渗透性、损伤自修复特性、对放射性核素具有良好的吸附作用等优点,被认为是一种合理的高放废物地质处置屏障。以黏土岩为研究对象,从黏土岩短期、长期力学特性等方面开展研究工作,主要内容如下：（1）进行黏土岩短期自然固结试验,确定了黏土岩的基本物理力学参数,主要包括前期固结压力、压缩指数等;（2）进行流-固耦合固结试验,试验结果表明盐水作用对黏土岩力学特性具有重要影响,且流-固耦合过程中的膨胀现象与黏土岩的黏土矿物含量和类型密切相关;（3）通过对黏土岩进行固结流变试验,研究黏土岩渗流-应力耦合作用下的长期力学特性,试验表明黏土岩具有明显的流变特性,且流变现象与载荷密切相关;（4）根据固结流变试验建立黏土岩一维流变本构模型,同时将模型计算结果与试验结果进行对比,分析表明,该模型能够很好地反映黏土岩一维固结流变特性。该研究对我国未来黏土岩高放废物处置库的规划、设计、选址和运营等具有重要的参考意义。 相似文献
4.
推导了含夹层盐岩储气库在地应力、注-采气压力和温度联合作用下的温度-渗流-应力（THM）-损伤耦合数学模型,该模型不仅包含了盐岩的热损伤效应,还考虑了气体渗透的Klinkenberg效应以及气体沿夹层层面流动对渗透规律的影响。在此基础上,结合金坛储气库建设,采用数值仿真技术,对储气库在注-采气过程中考虑THM耦合与不耦合情况下的气体渗透、温度分布以及应力分布规律进行了详细的对比分析和探讨,研究结果表明：含夹层盐岩储气库应力-渗透-温度耦合效应十分明显。该问题的研究,为全面深入分析盐岩储气库的安全性和实用性提供了思路及前提,具有重要的理论及实践意义。 相似文献
5.
黏土岩作为放射性核废料处置的备选介质,长期处于热-水-力耦合的复杂条件下。为研究围岩的长期稳定性,本文开展一系列不同围压和偏应力下的黏土岩加温-降温排水蠕变试验,得出以下结论:温度的升高会提升黏土岩的蠕变速率,延长衰减蠕变阶段的时间,但是降温过程中试样主要以冷缩变形为主并未见明显的蠕变变形;围压的降低以及偏应力的增加会提高黏土岩的蠕变速率,并且这种影响会随温度的升高明显加剧。基于试验结果,在Perzyna过应力理论的基础上引入蠕变硬化、蠕变损伤以及热损伤,建立了黏土岩热-水-力耦合蠕变模型。通过ABAQUS软件及其子程序对该模型进行数值实现,模拟结果与试验结果的对比初步表明该模型可以很好地描述热-水-力耦合条件下黏土岩的蠕变特性。 相似文献
6.
黏土岩作为放射性核废料处置的备选介质，长期处于热-水-力耦合的复杂条件下。为研究围岩的长期稳定性，开展了一系列不同围压和偏应力下的黏土岩加温-降温排水蠕变试验。得出以下结论：温度的升高会提升黏土岩的蠕变速率，延长衰减蠕变阶段的时间，但是降温过程中试样主要以冷缩变形为主，并未见明显的蠕变变形；围压的降低以及偏应力的增加会提高黏土岩的蠕变速率，并且这种影响会随温度的升高明显加剧。基于试验结果，在Perzyna过应力理论的基础上引入蠕变硬化、蠕变损伤以及热损伤，建立了黏土岩热-水-力耦合蠕变模型。通过ABAQUS软件及其子程序对该模型进行数值实现，模拟结果与试验结果的对比初步表明该模型可以很好地描述热-水-力耦合条件下黏土岩的蠕变特性。 相似文献
7.
高放废物地质处置库处于温度-渗流-应力（THM）多场耦合环境中,对高放废物处置库进行安全评估时,需进行多场耦合分析。然而高放废物处置库开挖引起硐壁附近围岩应力重分布,产生损伤,导致围岩热学参数（T）、渗流参数（H）和力学参数（M）发生变化,且在空间上分布不均匀,这将会对运营期处置库THM耦合演化过程产生显著影响。通过分析高放废物处置库温度-渗流-应力三场的耦合原理和处置库围岩损伤的分布和演化规律,定义了损伤变量和损伤演化准则,并将损伤变量与热学参数、渗流参数、力学参数以及多场耦合参数（Biot系数、Biot模量和温度排水系数）建立联系,将围岩损伤与温度-渗流-应力建立联系,形成了一个弹塑性损伤温度-渗流-应力多场耦合数值模型,然后利用建立的模型对瑞士Mont Terri高放废物地质处置库围岩加热试验进行模拟,对比了模拟值和试验值,比较了考虑开挖损伤和不考虑开挖损伤对高放废物地质处置库温度-渗流-应力的影响,并分析了在多场耦合作用下开挖损伤的演化规律。 相似文献
8.
针对核废料贮库围岩介质中的THM耦合作用下的岩体力学响应的特点,分析了THM耦合过程,利用O'C onnell的裂隙岩体等效弹性模量关系式中的裂隙密度概念意义,建立了温度作用下的裂隙密度与O da提出的裂隙张量之间的关系式;以裂隙结构面的开度、岩体裂隙数(包括受温度影响开通裂隙数)、裂隙连通率、附加应力、剪切膨胀等为研究对象,给出了具有THM耦合的渗流系数张量;在理论分析的基础上,建立了应力、应变、温度和热力学压力的关系方程式,给出了核废料贮库裂隙岩体介质热-液-力耦合的定解方程。为探讨核废料贮存裂隙岩体水热耦合迁移以及应力响应特征,提供了力学模型。 相似文献
9.
热-水-力(THM)耦合作用是岩石力学与环境地质中的重要基础理论问题,核废料地质处置库周围的缓冲材料和围岩中的热-水-力耦合现象将影响其力学稳定性、热传导性和渗透性,进而影响放射性核素在裂隙岩体中的迁移规律。核废料或放射性废料的地下深埋处置是国际上正在研究的永久性隔离的有效方法之一。因此,对核废料地质处置法安全性评估的一个重要内容就是对裂隙岩体中力学稳定性与构造应力、地下水渗流及热载荷等的耦合作用之数值模拟和评估。这已成为当前刻不容缓的重要的环境影响评价课题。笔者研究了温度场-渗流场-应力场中热传导系数和渗透率以及岩体力学参数的空间变异性,用实验方法研究三场耦合效应及裂隙岩体的场性能等效处理,试图建立热-水-力耦合作用的随机性数学模型及可视化数值模拟方法,为核废料地质处置安全性评估提供直观的新方法。 相似文献
10.
为揭示在渗流-化学溶解耦合作用下单裂隙渗透特性的变化规律,建立了描述二维渗流-化学溶解耦合作用的偏微分方程组,并利用COMSOL Multiphysics软件成功地求解该方程组。首先,模拟了文献[1]中的盐岩渗流-溶解耦合渗流试验结果,数值模拟结果与试验结果较为吻合,验证了数学模型的正确性和有效性。然后,利用分形理论生成了一个粗糙的裂隙面数字模型,着重分析了二维石灰岩粗糙裂隙面在水流、矿物溶解和输运过程中其渗透特性的变化规律。数值分析显示,（1）溶质浓度对裂隙面的溶解具有非常重要的作用,从而水流进口端的溶解厚度比出口端大得多。（2）裂隙的整体渗透性在初始时刻增加较慢,随着裂隙开度的增大和贯通,溶解速度会逐渐增大,是一个加速的过程。 相似文献
11.
The ATLAS III small scale in situ heating test aimed at assessing the thermo-hydro-mechanical (THM) effects on the Boom clay of the significant temperature gradients generated in this host rock as a consequence of the geological disposal of radioactive, heat-emitting wastes. This paper presents data on temperature, pore water pressure and total stress measured during the experiment and highlights several interesting observations regarding the thermal anisotropy and THM coupling in the Boom clay. The test has a simple geometry and well defined boundary conditions, which facilitates the comparison between measurement and numerical modeling studies. These studies included three dimensional coupled THM modeling of the test. The good agreement between measurement and numerical modeling of temperature and pore water pressure yields a set of THM parameters and confirms the thermo-mechanical anisotropy of the Boom clay. 相似文献
12.
Clayey soils in the vicinity of energy geostructures may be exposed to long-term periodic thermal cycles. The creep and consolidation behaviors of the clayey soils can be both rate-dependent and temperature-dependent, and the underlying physical mechanisms are merely investigated theoretically. In this study, based on the theory of thermodynamics, a fully coupled thermo-hydro-mechanical (THM) finite element (FE) program for saturated soils is developed for this purpose. The FE formulation accounts for the combined effect of rate and temperature through the novel concept of granular temperature. Simulations of THM coupled validation cases and a series of experimental observations on the soft Bangkok clay are carried out. The obtained numerical results exhibit good agreement with analytical solutions and laboratory measurements. It is found that three fundamental physical mechanisms contribute to the irreversible thermal contraction observed for normally consolidated and lightly overconsolidated clays under drained thermal cycles: (1) the thermal creep excited by mass exchange from adsorbed water to free water; (2) the mechanical creep induced by confining stresses; and (3) the increase in granular packing caused by the thermal expansion of soil particles. The thermal contraction generally stabilizes within a few thermal cycles, as a result of the noticeable reduction in the thermal creep rate. It is further demonstrated that the transient heat transfer and the heating rate can greatly influence the deformation of clays subjected to thermal cycles. 相似文献
13.
Following the need for understanding and quantifying the effect of temperature on the response of a candidate host formation for radioactive waste disposal, finite element modelling of an in situ thermal experiment has been carried out. Based on a thermo-hydro-mechanical (THM) finite element approach including a consistent thermo-plastic constitutive model, it has been possible to reproduce the THM response of a clay formation submitted to in situ thermal loading. The simulated large-scale experiment, called ATLAS was designed in the underground research facility (HADES-URF) in Mol, Belgium. After an extensive literature analysis on the thermal, hydraulic and mechanical characteristics of Boom Clay, laboratory tests were simulated to calibrate model parameters. The results of the finite element modelling of the ATLAS experiment were compared with in situ measurements and revealed the necessity to account for flow diffusion in all three directions through a 2D axisymmetric analysis. Finally, those results were interpreted in the light of elasto-thermoplasticity, which emphasizes the significant role of thermo-plastic processes in the global THM response of the clay formation. 相似文献
14.
The understanding of the thermo-hydro-mechanical behaviour of a clay barrier is needed for the prediction of its final in situ properties after the hydration and thermal transient in a radioactive waste repository. As part of the CEC 1990–1994 R&D programme on radioactive waste management and storage, the CEA (Fr), CIEMAT (Sp), ENRESA (Sp), SCK · CEN (B), UPC (Sp) and UWCC (UK) have carried out a joint project on unsaturated clay behaviour (Volckaert et al., 1996). The aim of the study is to analyse and model the behaviour of a clay-based engineered barrier during its hydration phase under real repository conditions. The hydro-mechanical and thermo-hydraulic models developed in this project have been coupled to describe stress/strain behaviour, moisture migration and heat transfer. A thermo-hydraulic model has also been coupled to a geochemical code to describe the migration and formation of chemical species. In this project, suction-controlled experiments have been performed on Boom clay (B), FoCa clay (Fr) and Almeria bentonite (Sp). The aim of these experiments is to test the validity of the interpretive model developed by Alonso and Gens (Alonso et al., 1990), and to build a database of unsaturated clay thermo-hydro-mechanical parameters. Such a database can then be used for validation exercises in which in situ experiments are simulated. The Boom clay is a moderately swelling clay of Rupellian age. It is studied at the SCK · CEN in Belgium as a potential host rock for a radioactive waste repository. In this paper, suction-controlled experiments carried out on Boom clay by SCK · CEN are described. SCK · CEN has performed experiments to measure the relation between suction, water content and temperature and the relation between suction, stress and deformation. The applied suction-control techniques and experimental setups are detailed. The results of these experiments are discussed in the perspective of the model of Alonso and Gens. The influence of temperature on water uptake was rather small. The measured swelling-collapse behaviour can be explained by the Alonso and Gens model. 相似文献
15.
在建立双重介质热-水-力耦合微分控制方程的基础上,提出了裂隙岩体热-水-力耦合的三维力学模型,对不同介质分别建立以节点位移、水压力和温度为求解量的三维有限元格式,开发了双重介质热-水-力耦合分析的的三维有限元计算程序,在有限元数值分析中不连续面应力计算采用等厚度空间8节点节理单元进行离散,而不连续面渗流和热能计算时采用平面4节点等参单元进行离散,这样保证了不同介质之间的水量、热量交换和两类模型接触处节点水头、温度和位移相等。通过高温岩体地热开发算例,揭示了在热-水-力耦合作用下不连续面处于低应力区,其张开度随运行时间的延长呈非线性增加,非稳定渗流阶段不连续面显著地控制着渗流场的整体分布,它的水头远高于拟连续岩体介质的水头,而进入稳定渗流阶段不连续面的控渗作用不明显,由于高温岩体地热开发系统中存在大规模的热量补给,不连续面对岩体温度场分布的影响并不显著。 相似文献
17.
岩土介质多场耦合问题需考虑诸多因素,温度、渗流及应力之间的耦合关系复杂,试验条件不易控制,且难以实现,因此,辅以数值模拟手段具有重要的意义。基于混合物理论,推导出岩土介质温度、渗流和应力耦合的数学模型及其控制方程,提出该数学模型的求解方法,以MATLAB语言为平台,将Abaqus程序作为一个模块嵌入迭代算法程序中,编制了多场耦合分析程序,并给出了2个典型算例验证该方法的有效性和实用性。然后,将建立的多场耦合模型和计算程序应用于石油钻井施工过程的模拟,重点分析井壁围岩内温度场、渗流场和应力场的变化规律,以及钻井液温度的变化对井壁稳定性的影响。研究成果对我国地下石油、核废料储存等工程设计和施工具有一定的指导意义。 相似文献
18.
The study of heat transfer, water flow, and swelling pressure development in engineered clay barriers and the evaluation of the influence of these phenomena on the barrier properties are important issues for predicting the performance of nuclear waste repository facilities. In this work, an experimental setup is presented especially meant to assess the response of the sand–bentonite mixture under conditions close to that of the buffer in a radioactive waste repository. A newly developed column device for laboratory testing of coupled thermo-hydro-mechanical (THM) behaviour of clay-buffer materials is introduced and its calibration, verification and the first experimental data are presented and discussed. The main features of the column device are: hydraulic and thermal gradients are possible to be applied; water content, suction and temperature development can be measured continuously at three locations along the sample height; swelling stress can be measured at top and the bottom of the sample. Measuring transient temperature, water content and suction simultaneously at the same height levels and with special care to minimise the sample disturbance is one of the advantages of the column device proposed here when compared to that previously reported in the literature. The main objectives of this paper are: (1) to describe the experimental device, (2) to introduce the sensors implemented and their calibration, and (3) to present and discuss the first experimental results obtained with the new equipment. The first experimental results show promise in the ability of the newly developed column device to provide reliable data for assessing the THM behaviour of expansive materials that are foreseen as buffer material in high level waste repositories. 相似文献
19.
Acta Geotechnica - This research work presents an experimental and numerical study of the coupled thermo-hydro-mechanical (THM) processes that occur during soil freezing. With focusing on the... 相似文献
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