高压实膨润土砌块接缝组合热−水−力耦合效应试验装置研制及应用  

Development and application of a testing apparatus to investigate coupled thermo-hydro-mechanical(THM)responses of densely compacted bentonite block and joint combination

作　　者：郑维翰 李涛[1] 冯硕 高玉峰[2] 刘月妙[2] ZHENG Wei-han;LI Tao;FENG Shuo;GAO Yu-feng;LIU Yue-miao(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]核工业北京地质研究院,北京100029

出　　处：《岩土力学》2021年第10期2908-2918,共11页Rock and Soil Mechanics

基　　金：国家国防科技工业局研究项目。

摘　　要：评估高放废物地下处置库缓冲材料的阻滞性能需要了解热−水−力(THM)耦合条件下高压实膨润土砌块与拼装接缝组合体的性能。为此,研制了一台膨润土砌块及接缝THM耦合特性试验仪,该装置由模型试验箱、砌块与接缝、温度控制、水力控制、数据测量与采集共5个系统构成。采用两块高庙子(GMZ)膨润土砌块和一条填有砂和膨润土颗粒的接缝制作砌块−接缝组合试样,在90℃的热边界和0.1 MPa的水力边界条件下进行了为期266 d的试验以检测试验装置设计的可行性。基于温度、体积含水率和膨胀力实测数据,获得了试样内部热、水和力三场的时空演化过程及规律。根据试样内部的干密度变化规律,建立了新的接缝愈合度定义式,并利用接缝变形观测数据计算了接缝愈合度。通过对接缝厚度与温度、体积含水率和膨胀力之间的关系进行回归分析,建立了相应的回归关系式。试验结果表明,该试验仪可用于核废物深地质处置缓冲材料的室内物理模拟试验。To evaluate the retardation capability of buffer materials in an underground repository for high-level radioactive waste,it is necessary to understand the performance of densely compacted bentonite block and joint combination under coupled thermo-hydromechanical(THM)condition.For this purpose,a testing apparatus for coupled THM responses of combined bentonite blocks and joints is developed.It consists of five parts,including the model test box,the combined block-joint sample,the temperature control system,the hydraulic control system,and the data measurement and acquisition system.Two compacted blocks composed of the Gaomiaozi(GMZ)bentonite and one joint filled with sand and bentonite powder were used to make the composite sample.To examine the feasibility of the design of this apparatus,the test was carried out under a thermal boundary condition of 90℃and a hydraulic boundary condition of 0.1 MPa for 266 days.Based on test data of temperature,volumetric moisture content and expansive force,the coupled THM responses and their spatiotemporal evolution rules were obtained.A new definition formula of joint-healingdegree was proposed on basis of variation of dry density in test sample.The joint-healing-degree was calculated through the measured change in joint thickness during the test.Regression analysis was conducted according to the relationship between the change in joint thickness and the coupled THM responses including temperature,volume moisture content and expansive force,and the regression formula was accordingly set up.It has shown that this apparatus can be used in the indoor physical simulation test of buffer materials for deep nuclear waste disposal.

关 键 词：高放废物处置 膨润土砌块 接缝 热−水−力耦合 模型试验 

分 类 号：TU443[建筑科学—岩土工程]