胶乳水泥模拟软岩蠕变行为的研究

发布时间：2018-06-03 22:07

本文选题：软岩 + 胶乳水泥　；参考：《青岛科技大学》2014年博士论文

【摘要】：复杂地质条件下深部软岩蠕变规律及其破坏机理的研究是地下工程的开展和深部围岩的支护等实际问题有深远的意义。随着地下工程和矿产开采不断向更深部发展,浅层岩石蠕变理论和相关经验已不能满足生产实际的需要。深部软岩面临的环境更加复杂,高温、复杂应力场、多介质等因素均影响其蠕变行为,蠕变试验开展难度大且时间周期长,影响蠕变的参数难以确定。相似试验为地下岩土工程的研究提供了一个新的方法,利用模型试验的方式对软岩蠕变行为进行模拟,可以迅速、经济的确定影响软岩蠕变的主要因素。本文拟寻求一种低弹性模量的相似材料以模拟软岩的蠕变特征。以相似准则为依据进行的模型试验,可以通过原型和相似材料的蠕变试验力学参数,建立两者之间的规律性。首先通过调整不同配比的胶乳水泥进行试验,并将模型试验结果与原型的试验参数比对,确定适合的相似材料：继而进行相似材料的蠕变试验反推软岩的蠕变规律和破坏机理。课题以国家自然科学基金“沥青、橡塑、软岩流变软化理论及相似模拟的研究”(51074094)等为背景进行研究。通过对软岩相似模型试验所遵循的相似准则推导确立了相似试验的相似指标,并以此为理论依据指导相似材料的配比和相似试验的开展。以丁苯胶乳为胶结剂的胶乳水泥配制相似材料,通过相关力学试验确定适合模拟软岩蠕变特性的配比,确定相似材料的养护方式和试验方法；通过动态力学频谱试验研究了温度对蠕变行为的影响；通过电镜试验对软岩及相似材料蠕变的微观形貌及破坏发生的微观特征进行研究；确定了软岩温度-应力条件下的蠕变模型并对原型和模型的参数进行拟合；结合工程实际,利用FLAC进行了蠕变数值模拟,证明胶乳水泥可能较好的模拟软岩的蠕变行为。试验结果、参数拟合及数值模拟结果得到了相互验证,且符合相似准则。结果证明,所研制的相似材料可以较好的模拟软岩的蠕变规律。对该材料开展更多的试验,来寻求软岩的蠕变规律,可用于指导工程实际工作。本文开展的具体研究工作如下： 1.以相似理论为理论依据,通过量纲分析法推导软岩线弹性阶段和蠕变阶段所遵循的相似准则,并考虑温度、密度等对相似准则的影响。对获得的相似判据进行研究,确定相似试验所需要依赖的物理参量之间的相互关系,研究了温度、时间、应力及密度等相似性对相似试验开展可能造成的影响。该相似准则对相似材料的选取和配比的确定、相似试验的开展起指导意义,并对相似试验的结果进行验证； 2.选择以胶乳水泥作为模拟软岩蠕变现象的相似材料。分别利用三种胶乳配制胶乳水泥试样,分析作为相似材料的可行性,确定了以丁苯胶乳和水泥作为胶结料、以砂为骨料作为相似材料的主要组成部分；研究了相似材料的配比及制作过程中的养护、试验条件；针对软岩相似材料的特点及标准试样的要求,设计了适合相似材料的专用模具及装置,包括可调整机架及独立模具,能够较好的对试样进行密实并顶出试样。模具一体成型无接缝,克服了对开模可能对试样造成的模具对接不严密、难以压实等不良影响。模具及装置保证了制作相似材料的标准试样的尺寸精确度,提高了试样制作效率； 3.开展相似试验。研究页岩的基本力学性能及蠕变特征,并利用扫描电镜对软岩断口进行观测,从微观结构分析软岩的蠕变破坏机理：利用时温等效理论推导了不同温度下软岩试验的时间-蠕变关系和温度-蠕变关系。对不同含砂量的丁苯胶乳水泥进行了单轴蠕变试验,并利用动态力学频谱仪对不同温度、不同配比的材料进行蠕变试验,研究了含砂量和温度对蠕变曲线的影响,通过对比确定了以水泥：胶乳：砂为1：0.2：2的胶乳水泥作为软岩相似材料。该材料兼具水泥的强度和胶乳的良好蠕变性能,可以较好的模拟软岩的蠕变破坏规律,原型和模型有较高的相似性；同时证明了胶乳水泥具有较高的温敏性,含砂量过大时,胶乳水泥的抗压强度反而下降。电镜试验也表明,胶乳水泥和软岩在微观结构和破坏方式上有一定的相似性。 4.在研究软岩和相似材料蠕变规律的基础上,推导了Burgers模型的本构方程和蠕变方程,利用Oringin软件对试验参数进行拟合并获得蠕变主要物理参量的数值；以三维Burgers模型为蠕变模型,拟合了不同温度下的移位因子,并建立了同一应力条件下任意温度下软岩的蠕变柔量表达式。 5.利用FLAC软件蠕变模块中的Burgers模型对单轴蠕变试验和工程巷道进行数值模拟,证明20℃的胶乳水泥试验参数可较好的模拟50℃的软岩蠕变规律；通过巷道数值模拟验证了原型和模型的蠕变位移、应力分布和蠕变速率等符合相似准则。也证明了试验、拟合参数和数值模拟结果等与相似准则具备较高的一致性；结果表明胶乳水泥可以较好的模拟原型的蠕变规律。
[Abstract]:The study on the creep law of deep soft rock and its failure mechanism under complex geological conditions is of profound significance to the development of underground engineering and the support of deep surrounding rock. With the development of underground engineering and mineral exploitation, the creep theory and related experience of the shallow rock can not meet the needs of production practice. The environment of rock is more complex, high temperature, complex stress field, multi medium and other factors all affect its creep behavior. The creep test is difficult and time period is long and the creep parameters are difficult to be determined. Similar test provides a new method for the study of underground geotechnical engineering. Line simulation can quickly and economically determine the main factors affecting the creep of soft rock. This paper intends to find a similar material with low modulus of elasticity to simulate the creep characteristics of soft rock. The model test based on the similarity criterion can establish the regularity between the prototype and the creep test parameters of similar materials. The latex cement with different proportions was tested, and the model test results were compared with the experimental parameters of the prototype to determine the suitable similar materials. The creep test of similar materials was carried out to reverse the creep law and failure mechanism of the soft rock.
The subject takes the National Natural Science Fund "asphalt, rubber, plastic, soft rock rheology and softening theory and similar simulation study" (51074094) as the background to study. The similarity criterion of similar test is established by the similarity criterion derived from the similar model test of soft rock, and it is used as the theoretical basis to guide the ratio and similar test of similar materials. The similar material was prepared by the latex cement of styrene butadiene latex as the cementing agent. The ratio of the creep properties suitable for the simulated soft rock was determined by the related mechanical test, the curing mode and the test method of the similar materials were determined. The effect of temperature on the creep behavior was studied by dynamic mechanical spectrum test, and the soft rock and the soft rock were tested by electron microscope test. The microscopic morphology of the similar material creep and the microscopic characteristics of the failure are studied. The creep model under the temperature stress condition of the soft rock is determined and the parameters of the prototype and the model are fitted. The creep numerical simulation is carried out by FLAC, which proves that the latex cement may well simulate the creep behavior of the soft rock. The results show that the results of parameter fitting and numerical simulation are verified and accords with the similarity criterion. The results show that the similar material can be used to simulate the creep law of soft rock better. More experiments are carried out to the material to seek the creep law of soft rock, and it can be used to guide the practical work of the project. Below:
1. using the similarity theory as the theoretical basis, the similarity criterion followed by the elastic and creep stages of the soft rock line is derived by the dimensional analysis method, and the influence of the temperature and density on the similar criteria is considered. The similarity criterion obtained is studied to determine the relationship between the parameters of the physical and physical parameters that the similar test needs to be dependent on, and the temperature is studied. The similarity of stress and density may affect the similarity test. The similarity criterion is of guiding significance to the selection of similar materials, the determination of the ratio of similar materials, the development of similar tests, and the verification of the results of similar tests.
2. choose latex cement as a similar material to simulate the creep of soft rock. Using three kinds of latex to prepare latex cement samples, the feasibility of being used as similar material is analyzed. The main components of the similar material are styrene butadiene latex and cement as cementing material and sand as aggregate. The ratio and production of similar materials are studied. In the process of maintenance, test conditions, in view of the characteristics of similar materials of soft rock and the requirements of standard samples, special moulds and devices suitable for similar materials are designed, including adjustable frame and independent die, which can be better to compact and top out the specimen. The mould and device guarantee the size accuracy of the standard samples made of similar materials and improve the production efficiency of the sample.
3. carry out similar experiments. Study the basic mechanical properties and creep characteristics of shale, and observe the fracture of soft rock by scanning electron microscope and analyze the creep failure mechanism of soft rock from microstructure: the time creep relationship and temperature creep relationship of soft rock under different temperatures are derived by using the time temperature equivalence theory. The uniaxial creep test of styrene latex cement was carried out, and the creep tests of materials with different temperatures and different proportions were carried out by dynamic mechanical spectrum analyzer. The effects of sand content and temperature on the creep curves were studied. By comparison, cement: latex: latex cement as 1:0.2:2 was used as a similar material for soft rock. The strength of the mud and the good creep property of the latex can better simulate the law of the creep failure of the soft rock, and the prototype and the model have high similarity. At the same time, it is proved that the latex cement has high temperature sensitivity, and the compressive strength of latex cement decreases when the content of sand is too large. The electric mirror test also shows that the latex cement and soft rock are in the micro junction. There is a certain similarity in the way of destruction and destruction.
4. based on the study of the creep law of soft rock and similar materials, the constitutive equation and creep equation of the Burgers model are derived. The numerical values of the main physical parameters are obtained by using the Oringin software to obtain the main physical parameters of the creep. The three-dimensional Burgers model is used as the creep model, and the displacement factors at different temperatures are fitted, and the same one is established. Creep compliance expression of soft rock at any temperature under stress condition.
5. using the Burgers model in the FLAC software creep module to simulate the uniaxial creep test and the engineering roadway, it is proved that the test parameters of the latex cement at 20 C can better simulate the creep law of the soft rock at 50 C, and the creep displacement of the prototype and the model is verified by the numerical simulation of the tunnel, and the stress distribution and the creep rate are similar to the similar quasi accurate. It is also proved that the test, the fitting parameters and the numerical simulation results are in good agreement with the similar criteria, and the results show that the latex cement can better simulate the creep law of the prototype.
【学位授予单位】：青岛科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU45

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