峰后碎裂岩体破坏能量转化与纤维喷射混凝土支护特性研究

发布时间：2018-04-30 01:01

本文选题：峰后碎裂围岩 + 应变能密度理论　；参考：《山东大学》2015年硕士论文

【摘要】：隧道施工建设前期的初期支护,作为整个施工工序极为重要的一环,国内的研究尚处于经验指导施工阶段,缺乏相关的工程问题研究,尤其是峰后碎裂围岩条件下配套的隧道建设初期支护研究。对于峰后碎裂围岩破坏机理的认识问题,已引起岩土工程领域学者们的浓厚兴趣。同时,相应的隧道初期支护对策以及最优化,也成为工程技术领域急需解决的一个工程难题。本文从峰后碎裂围岩体大变形导致初期支护喷射混凝土破裂这一工程现场问题需求出发,从能量平衡的角度,对峰后碎裂岩体的破坏变形特性进行研究。根据岩体裂隙发生及破坏过程中,整个围岩系统能量的变化来判断研究对象围岩体的稳定性,更好的解释峰后碎裂围岩变形破坏的内在机制。本文从峰后裂隙围岩局部大变形导致初期支护喷射混凝土破坏这一工程现场问题需求出发,基于应变能密度理论研究,借助于UDEC数值模拟工具,以塑钢纤维喷射混凝土中心，结合室内试验和工程现场试验,试探性研究峰后碎裂岩体的变形破坏特性及塑钢纤维喷射混凝土在初期支护中支护作用。本文的主要研究内容可分为以下四点：1、以受工程开挖影响围岩松动圈中的峰后碎裂岩体为研究对象,从能量转换的角度出发,基于应变能密度理论, 把岩石的全应力应变曲线分为两种类型,统一地用数学公式解释其能量转换关系,并进一步提出适用于峰后碎裂围岩变形破坏的能量判别准则。2、通过Fish语言编程,把应变能密度理论以破坏准则的形式引入UDEC数值模拟软件,实现了峰后碎裂岩体从局部破坏到完全破坏的整个损伤演化过程的数值模拟分析。通过岩体试件的室内试验与改进后的数值模拟结果对比,验证改进后UDEC程序的科学有效性,为下一步的研究塑钢纤维喷射混凝土的支护作用优必选提供支持。3、在室内试验的基础上,提出一种新型吸能型塑钢纤维喷射混凝土材料,对塑钢纤维喷射混凝土进行优化配比,选定最优塑钢纤维掺量和纤维长度,并给出其必要的力学性能参数。利用改进的UDEC数值模拟软件研究新型塑钢纤维喷射混凝土在碎裂峰后围岩体条件下的支护特性。4、结合工程现场原位试验,改进喷射混凝土施工工艺,提出一种新型分离式喷混施工工艺,并对塑钢纤维喷射混凝土作为初期支护的效果进行评价分析,确定其喷层的最优厚度。
[Abstract]:As an important part of the whole construction process, the initial support in the early stage of tunnel construction construction is still in the stage of experience guiding construction, and there is a lack of research on related engineering problems. Especially the initial supporting research of tunnel construction under the condition of fractured surrounding rock after peak. The understanding of the failure mechanism of the post-peak fractured surrounding rock has aroused great interest of the scholars in the field of geotechnical engineering. At the same time, the corresponding initial supporting countermeasures and optimization of tunnel have become an urgent engineering problem in the field of engineering technology. In this paper, from the point of view of energy balance, the failure and deformation characteristics of post-peak fractured rock mass are studied from the point of view of the field problem of the initial support shotcrete rupture caused by the large deformation of the surrounding rock mass after the peak. According to the change of energy of the whole surrounding rock system during the occurrence and failure of rock fracture, the stability of the surrounding rock body is judged, and the internal mechanism of the deformation and failure of the fractured surrounding rock after the peak is better explained. In this paper, based on the research of strain energy density theory and UDEC numerical simulation tool, the center of plastic-steel fiber sprayed concrete is developed according to the demand of local large deformation of post-peak fissure surrounding rock which results in the initial support shotcrete destruction, which is based on the theory of strain energy density. Combined with laboratory tests and engineering field tests, the deformation and failure characteristics of post-peak fractured rock mass and the support function of plastic-steel fiber shotcrete in the initial support are studied tentatively. The main research contents of this paper can be divided into the following four points: 1. Taking the post-peak fractured rock mass in the loosening zone of surrounding rock affected by engineering excavation as the research object, from the point of view of energy conversion, Based on the theory of strain energy density, the total stress-strain curve of rock is divided into two types. Furthermore, the energy criterion. 2, which is suitable for the deformation and failure of post-peak fractured surrounding rock, is proposed. The strain energy density theory is introduced into the UDEC numerical simulation software in the form of failure criterion through Fish programming. Numerical simulation analysis of the whole damage evolution process from local failure to complete failure of post-peak fractured rock mass is carried out. The scientific validity of the improved UDEC program is verified by comparing the laboratory test of rock mass samples with the results of the improved numerical simulation. In order to study the supporting function of plastic-fiber sprayed concrete in the next step. 3. On the basis of indoor test, a new type of plastic-steel fiber sprayed concrete material is put forward to optimize the proportion of plastic-steel fiber sprayed concrete. The optimum fiber content and fiber length are selected and the necessary mechanical properties are given. By using the improved UDEC numerical simulation software, the supporting characteristics of new type plastic-steel fiber sprayed concrete under the condition of surrounding rock mass after the crack peak are studied. Combined with the in-situ test of the project, the construction technology of the sprayed concrete is improved. In this paper, a new type of separate shotcrete construction technology is put forward, and the effect of plastic-steel fiber shotcrete as initial support is evaluated and analyzed, and the optimum thickness of the spray layer is determined.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.7

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