【作者】 王伟超；

【导师】 刘希亮；

【作者基本信息】 河南理工大学 ， 矿山建筑工程， 2016， 博士

【摘要】 盐岩矿床经过水溶开采后形成的溶腔被世界各国公认是液化天然气储备的理想场所。随着我国能源战略储备工程的实施,盐穴储气库作为重要的储备工程设施,对我国能源储备和天然气调峰具有不可或缺的重要作用。由于盐穴储气库在水溶开采时会产生溶蚀裂纹,裂纹盐岩在注采气过程中,受到周期荷载作用从而产生疲劳损伤;同时,深部盐岩受到的围压、温度变化也将对其损伤过程产生一定影响。针对这些问题,本文以河南省第一个拟建盐穴储气库——平顶山盐穴储气库为研究重点,通过扫描电镜、体视荧光显微镜分析了叶舞盐岩的微细观组构特征;通过单、三轴压缩试验和声发射定位等试验,研究了盐岩的损伤演化力学特性;通过理论分析,构建了基于声发射定位点数的损伤模型和疲劳损伤累积演化模型。主要包括如下几个方面:(1)根据河南叶舞盐田勘探地质资料,利用扫描电镜和体视显微镜研究了叶舞盐岩的细观组构特征,对国内拟建盐穴储气库盐岩溶蚀特征进行了分析,研究了盐岩的溶解机理和溶解特性。(2)通过单轴、三轴压缩试验,研究了河南叶舞盐岩的损伤演化力学特性,基于能量耗散理论,分析了盐岩损伤破坏过程中的能量特征;利用多通道声发射信号采集系统,对盐岩受荷破坏过程中的声发射信号进行定位监测,对盐岩损伤演化过程进行了分析研究;构建了基于声发射定位点参数的损伤模型,该模型能够较好地描述完整盐岩的损伤演化过程。(3)利用岩石力学伺服控制试验系统,对不同几何参数下的裂纹盐岩进行了三轴压缩试验研究,分析了不同裂纹对盐岩的三轴压缩强度、变形特性以及能量耗散特征的影响规律,及裂纹盐岩在不同围压作用下的破裂模式。通过对含表面裂纹盐岩在单轴压缩下的裂纹扩展演化试验研究,分析了表面裂纹对强度和变形的影响,探讨了裂纹扩展及贯通模式。(4)在储气库注采过程中,腔体附近的盐岩体处于加、卸载的周期荷载作用。利用岩石力学伺服控制试验系统对不同参数的裂纹盐岩进行了单轴疲劳试验,研究了不同预制裂纹盐岩的疲劳破坏特性以及破坏过程中的能量特征,并将疲劳破坏过程与简单加载过程结果进行了对比分析。此外,通过恒荷载疲劳和变荷载疲劳试验,对盐岩在周期循环荷载作用下的抗拉疲劳破坏特征及其破坏机理进行了研究,分析了巴西劈裂过程中破坏断口的形貌特征。(5)在总结损伤变量定义方法的基础上,分析了利用不同方法定义损伤变量的可行性。根据盐岩在单轴循环加载过程中的强度和变形规律,建立了能表征循环荷载作用下盐岩疲劳损伤累积演化规律的曲线模型,并对损伤累积演化曲线模型中的参数物理意义进行了分析,该损伤累积演化模型可以较好地描述裂纹盐岩的损伤累积演化特性。更多还原

【Abstract】 The cavern,formed after solution mining on the salt rock deposit,is recognized as an ideal place for natural gas storage around the world.With the implementation of the energy conservation engineering,the salt cavern gas storage,as an important engineering facility,plays a significant role on energy storage and regulation in China.As the salt cavern gas storage will produce corrosion cracks in solution mining,the crack salt rock is subjected to cyclic loading resulting in fatigue damage in the process of gas injection and production.Meanwhile,the deep salt rock is affected by temperature,pressure variation which has a certain impact on the fatigue damage process.In order to solve these problems,this paper mainly focuses on the study of the first proposed salt cavern gas storage in Pingdingshan,Henan Province,and analyzes the microscopic characteristics of the Yewu salt rock by scanning electron microscope and stereo fluorescence microscope.The issues presented above were studied by uniaxial,triaxial compression test and acoustic emission location etc,and by theoretical analysis and model construction as well.This paper mainly involves the following aspects:(1)According to the geological exploration data of Yewu Salt field of Henan Province,by studying the microstructure characteristics of Yewu salt rock by means of scanning electron microscopy and stereo microscope,and by analyzing the dissolution characteristics of proposed salt cavern gas storage in domestic,the dissolution mechanism and dissolution characteristics of salt rock were studied.Meanwhile,the thermal damage mechanism of salt rock under ground temperature was studied by simulating ground temperature condition and using the theory of dislocation and diffusion creep.(2)The mechanical properties of damage evolution of Yewu salt rock of Henan Province under the complex conditions were studied through the uniaxial and triaxialcompression tests.And,based on the energy dissipation theory,the energy characteristics of salt rock were analyzed in the process of damage and failure.The acoustic emission signal was monitored in the process of damage of salt rock under the load by using the multi-channel acoustic emission signal acquisition system.The acoustic emission events were located by using Geiger positioning algorithm,and the damage of evolution process of salt rock was analyzed.The damage model based on acoustic emission location point parameter was constructed,which can better describe the damage evolution process of the whole salt rock.(3)The triaxial compression tests were carried out on salt rock with different geometrical parameters(different lengths and different dip angles)by using the rock mechanics servo control test system to discuss the influences of different cracks on the triaxial compressive strength,deformation characteristics and energy dissipation characteristics of salt rock,and to analyze the fracture modes of the cracked salt rock under different confining pressures.The experimental study of evolution of crack propagation aimed at salt rock with apparent crack under uniaxial compression was carried out and the crack propagation and coalescence mode were discussed.(4)The salt rock mass near the cavity are subject to periodic load of loading and unloading in the process of injection and production of gas storage.The uniaxial fatigue tests were carried out on crack salt rock with different parameters by using the rock mechanics servo control test system,the fatigue failure characteristics and energy characteristics in the process of failure of the salt rock with different prefabricated cracks were investigated,and the results of fatigue failure process and simple loading process were analyzed comparatively.In addition,the tensile fatigue failure characteristics and failure mechanism of salt rock in the fatigue test of constant load and variable load under cyclic loading were studied,and the morphology characteristics of fractured profile in the process of Brazilian split was analyzed.(5)Based on the current research of rock damage variable and the summary of different definitions of damage variables,this research paper analyzed comparatively the feasibility of using different definitions of damage variables.Based on the development of strength and deformation of salt rock under uniaxial cyclic loading,a curve model was established to characterize the cumulative evolution of salt rock fatigue damage under cyclic loading,and the physical meaning of the parameters in the curve model of damage cumulative evolution were analyzed.The damage accumulation evolution model can sufficiently describe the damage accumulation evolution characteristics of cracked salt rock.更多还原