断层软弱介质注浆扩散加固机理及工程应用

发布时间：2018-06-14 12:49

本文选题：软弱介质 + 劈裂扩散理论模型　；参考：《山东大学》2015年博士论文

【摘要】：随着我国国民经济的快速发展,对矿产资源、水利资源及交通工程的需求日益增大,跨海隧道、公路隧道、深井矿山、城市地铁等一大批地下工程投入建设,地下工程建设正向地质条件复杂多变,工程建设难度高的地域延伸和转移。软弱介质充填断层是地下工程建设中经常遭遇的不良地质,在地下水及开挖应力作用下,极易发生软弱介质的结构破坏,形成导水通道和薄弱结构面,引发突水突泥、坍塌失稳及地表沉降等地质灾害,是地下工程建设中的主要灾害源。注浆作为有效的治理方法,广泛应用于软弱介质充填断层的灾害治理中,但是,受限于注浆工程的隐蔽性与被注介质的各向异性,浆液与被注岩土体之间的相互作用过程极其复杂,注浆理论的研究远远滞后于工程实践,亟需深入研究。本文采用理论分析、模型试验、数值模拟和现场试验相结合的研究方法,选取典型软弱介质土体为研究对象,基于非线性压缩模型,研究了注浆扩散加固机理,通过试验与数理分析方法建立了注浆加固前后土体力学及渗透性能的定量关系；在此基础上分析了地下工程注浆加固前后稳定性,建立分段梯次增压复合式注浆方法,并在依托工程成功应用,取得了一系列研究成果。(1)根据介质物理结构特征的不同对断层充填介质进行了分类,研究了不同类型介质的扩散及加固模式,揭示了注浆扩散发生条件及加固作用过程,获得了可描述注浆加固效果的主要指标参数。(2)基于土体非线性压缩模型,并考虑劈裂注浆过程中浆液流场与土体应力场的耦合作用,建立了劈裂注浆扩散理论模型,获得了劈裂通道宽度的空间分布方程,分析了注浆压力、劈裂通道宽度、浆液扩散半径三者之间的关系。将土体压缩模量、土体孔隙率、土体渗透率作为注浆效果评价指标,提出了注浆有效加固半径及劈裂注浆参数的确定方法。(3)自主研发了一套大比例三维断层软弱充填介质注浆模型试验系统,可还原软弱介质真实注浆环境,开展了分段注浆模拟试验,并实时监测注浆过程多元信息。研究了软弱介质中注浆扩散过程,获得注浆扩散不同阶段注浆压力及速率的变化特征和浆液扩散过程中压力场时空演化规律,揭示了分段注浆扩散加固机理。通过开挖揭露和取样测试,分析了浆脉厚度变化及空间分布特征,建立了试验条件下注浆加固前后力学参数及渗透系数的定量关系。(4)基于上述定量关系,采用流固耦合理论建立地下工程开挖的有限元模型,对比分析注浆前后岩土体稳定性及涌水量,对注浆加固参数选择方法进行了验证。(5)建立了分段梯次增压复合式注浆方法,阐述了复合注浆技术的原理及设计方法。研究成果在南京地铁上元门车站临江破碎带注浆加固工程成功应用,取得了良好的治理效果,可为类似工程提供借鉴,具有广阔的应用前景。
[Abstract]:With the rapid development of China's national economy, the demand for mineral resources, water resources and transportation projects is increasing day by day. A large number of underground projects, such as cross-sea tunnels, highway tunnels, deep well mines, urban subways, etc., have been put into construction. The geological conditions of underground engineering construction are complex and changeable, and the construction of underground engineering is difficult to extend and transfer. The fault filled with weak medium is often encountered in bad geology in underground engineering construction. Under the action of groundwater and excavation stress, it is easy to occur structural damage of weak medium, forming water conduction channel and weak structural surface, and causing water inrush and mud inrush. Collapse instability and surface subsidence are the main disaster sources in underground engineering construction. As an effective treatment method, grouting is widely used in disaster control of fault filled with weak medium, but limited by the concealment of grouting engineering and anisotropy of injected medium. The process of interaction between grouting and injected rock is extremely complex, and the research of grouting theory lags far behind engineering practice. In this paper, theoretical analysis, model test, numerical simulation and field test are used to study the mechanism of grouting diffusion reinforcement based on nonlinear compression model. The quantitative relationship of soil mechanics and permeability before and after grouting reinforcement is established by means of test and mathematical analysis, and the stability of underground engineering before and after grouting reinforcement is analyzed, and the composite grouting method of step by step pressurization is established. Based on the successful application of the project, a series of research results have been obtained. (1) according to the different characteristics of the physical structure of the medium, the fault filling media has been classified, and the diffusion and reinforcement modes of the different types of media have been studied. In this paper, the conditions of grouting diffusion and reinforcement process are revealed, and the main parameter of grouting reinforcement effect is obtained. Based on the nonlinear compression model of soil, the coupling effect of slurry flow field and soil stress field is considered in the process of splitting grouting. A theoretical model of split grouting diffusion is established, and the spatial distribution equation of split channel width is obtained. The relationship among grouting pressure, split channel width and slurry diffusion radius is analyzed. The compression modulus, porosity and permeability of soil are taken as the evaluation indexes of grouting effect. The method of determining the effective reinforcement radius and the parameters of splitting grouting is put forward. A set of large scale 3D fault grouting model test system for soft filling medium is developed, which can reduce the real grouting environment of weak medium. Segmented grouting simulation test was carried out, and multi-information of grouting process was monitored in real time. The process of grouting diffusion in soft medium is studied. The variation characteristics of grouting pressure and rate in different stages of grouting diffusion and the space-time evolution law of pressure field in grouting diffusion process are obtained, and the mechanism of grouting diffusion reinforcement is revealed. Through excavation exposure and sampling test, the variation and spatial distribution characteristics of grouting vein thickness are analyzed, and the quantitative relationship between mechanical parameters and permeability coefficient before and after grouting reinforcement under test conditions is established. The finite element model of underground engineering excavation is established by using fluid-solid coupling theory. The stability and water inflow of rock and soil before and after grouting are compared and analyzed. The selection method of grouting reinforcement parameters is verified. The principle and design method of compound grouting technology are described. The research results have been successfully applied in the grouting reinforcement project of the breakage zone near the river of Shangyuanmen Station of Nanjing Metro, and good treatment effect has been obtained, which can be used as a reference for similar projects and has a broad application prospect.
【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU472;TU94

【引证文献】