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裂隙岩体复合防渗堵水浆液试验及作用机理研究

Study on Test and Operation Mechanism of the Watertight and Water Shut-off Grout in Fractured Rock Mass

【作者】 何忠明

【导师】 彭振斌;

【作者基本信息】 中南大学 , 地质工程, 2007, 博士

【摘要】 随着现阶段地下工程建设发展的规模不断扩大和水利工程的不断兴起,注浆技术在国内外得到越来越广泛的应用。注浆的主要目的是将不符合工程要求的岩土改良为高品质的符合工程要求的岩土,使即有资源得到充分利用。由于注浆工程属于隐蔽工程,使得注浆技术的发展至今为止还很不成熟,在注浆实践运用过程中有时还存在着理论落后于实践的情况。注浆材料及浆液性能的研究是注浆技术中不可缺少的一个重要组成部分。注浆之所以能够起到防渗堵水或加固的作用,主要是由于注浆材料在注浆过程中发生由液相到固相的转变的结果。而注浆浆液的性能关系着浆液注入裂隙岩体后的注浆效果,对注浆工程来讲是至关重要的。论文通过采用收集前人资料、室内试验、理论分析以及现场工程应用等研究方法,对裂隙岩体注浆效果的影响因素作了归纳和总结,对裂隙岩体复合防渗堵水浆液的浆材成分、浆材配比、浆液性能、浆液固结机理、浆液防渗堵水机理及浆液渗透机理做了研究,并在此基础上探讨了该浆液在裂隙岩体防渗堵水工程中的运用。对于裂隙岩体防渗堵水注浆来说,不管使用的是何种注浆材料,其注浆效果最主要的影响因素是注浆材料本身的性质、裂隙岩体的工程力学性质、注浆设计参数及现场注浆工艺等。经过室内试验,初步确定裂隙岩体复合防渗堵水浆液由粘土、水泥、水玻璃、NH4H2PO4、水等成分组成。该浆液配比经试验确定有一个大概最佳范围,但在应用于具体工程时还应根据工程现场的实际情况进行室内试验及现场试验,以确定该工程各注浆段的最优配方。浆液的性能测试结果表明,浆液具有良好的稳定性、可控性及可注性,其浆液注入岩层后形成的结石体具有很好的防渗堵水效果及耐久性,且浆液的性能与浆液各组份的含量有关。通过采用扫描电镜观察等试验方法对裂隙岩体复合防渗堵水浆液固结过程进行进一步研究,结果发现该浆液的固结过程即是浆液各组成成分之间互相发生一系列物理化学反应的过程,包括水泥的水化反应、粘土的水化、NH4H2PO4对水泥水化反应的阻滞作用、水泥水化物与粘土颗粒之间的反应、水泥与水玻璃之间的反应及粘土与水玻璃之间的反应等。而浆液固结过程的热力学分析表明上述反应中晶体和胶体生成过程是新相形成、生长的过程,其推动力可以用自由能差来描述;浆液动力学分析则表明反应进行程度系数αb有增大的趋势,说明上述反应具有自发性。裂隙岩体复合防渗堵水浆液的结构形成过程与水泥浆液的结构形成过程不一样。根据浆液塑性强度曲线的结构特征可将浆液的结构形成过程分为以下三个状态:液态、凝胶态及固态,在上述“三态”中浆液均能进入防渗堵水状态,只是其防渗堵水方式和能力有很大的不同。而浆液结石体在注浆孔内可沿裂隙方向分为三个区:密实区、稳定区及松散区。在裂隙岩体防渗堵水注浆过程中,松散区、稳定区及密实区等“三区”是随着注浆时间交互变化的。在裂隙岩体中采用注浆方法防渗堵水,浆液能够起防渗堵水的作用机理就是浆液对地下水的流动有一个与水流方向相反的阻挡作用,即浆液的流动应是水渗流的逆过程。若将浆材按与水类似的牛顿流体来考虑,裂隙渗流与注浆运动过程的本质是一致的,牛顿流体浆材的流动应当符合有关的裂隙水力学公式。论文根据国内外学者已推导出来的一些裂隙水力学公式,考虑裂隙岩体复合防渗堵水浆液属于宾汉流体,在浆液流动时具有流核,推导建立了该浆液在岩体平面裂隙及倾斜裂隙中的渗流规律模型。工程应用研究结果表明,裂隙岩体复合防渗堵水浆液在裂隙岩体中的注浆工艺与其它注浆浆液的工艺类似。但采用该浆液对裂隙岩体注浆时,应采用三级搅拌法及大循环注浆方式,注浆时还应根据工程现场地层实际情况进行控制和调节浆液注入量及配方,来获得最佳注浆效果。

【Abstract】 Ground project enlarged and the water conservancy project prospered at present, grouting has been widely used at home and abroad. Grouting purposes most to reinforce the rocks which don’t meet the requirement of the project into the high-qualitied rocks that meet the requirement so that it can make full usage of the resources. Due to grouting engineering belonging to hidden project, the development of it is un-mature so far and the cases of theory falling behind practice remains now and then during the process of applying grouting in practice. Study on grouting material and behavior of grout plays a significant role in the technology of grouting. Grouting can seal up to shut off water and reinforce stratum because the materials can change liquid phase into solid phase. The grouting effect relates to the behavior of grout after being injected into the fractured rock mass, which is significant to grouting engineering.Base on collecting the past data, indoor test and theoretic analysis and appliance in the scene of projection, the affecting factors of the grouting effect has been concluded and summarized inhere. Furthermore, the paper has done research on the compound watertight grout components, proportion, behavior, consolidation mechanism, antiseepage mechanism and infiltration mechanism, and discusses the application in the project of fractured rock mass.For watertight and water shut-off grout in fractured rock mass, there is no matter that which material is used. The uppermost influential factor is the property of the material, the engineering mechanical property, design parameter for grouting and grouting technology.Through the laboratory test, it confirms preliminarily that the watertight and water shut-off grout in fractured rock mass is made up with clay, cement, water glass, NH4H2PO4, water, etc.. The proportioning has a general best range through experiments, however, when applying it in the specified projection, the grout should be according to the practical case at spot as well as the practical experiment, so as to ensure the best formulation. The property of grout test has manifested that grout has excellent stability, controllability condition, grout-ability and the stone body formed after the grout has infused into the terrane has showed good effect and permanence, and the property of grout relates to the content of the components of it.The paper has maked further research on the process of consolidation of the grout by some test methods like SEM and found that the process is a series of physical chemical reaction among each component, which includes prehydration reaction of cement, prehydration of clay, inhibitory activate from NH4H2PO4 to prehydration of cement, the reaction between cement hydrate and clay particle, the reaction between cement and water glass and the reaction between clay and water glass. The thermomechanical analysis for the process of consolidation shows that crystal and colloid created in the reaction is kainotyping and growing. Its propulsion can be described by free energy difference. And the analysis manifests that the reaction carrying-coefficient(ab) has the trend to increase, which shows the reaction has autonomy.The forming process of the grout structure is different from the cement slurry’s. In accordance to structural feature of it’s plastic strength curve, the forming process of the grout structure can be divided into liquid state, gel state and solid state. And the grout can seal up and shut off water in the process. But there are big differences in the mode and the capability. The stone body is divided into three zones in grouting hole along the crack direction. They are consolidation zone, stability zone and porosity zone. And the three zones can interconvert in company with the grouting time in the grouting process.Grouting is adapted in fractured rock mass to seal up and shut off water, and the grout can do work because of the contrary resist function to direction of groundwater flowing. That is reverse process of water flow. If the grout material is considered as Newtonian fluid like water, the process of grouting moving is coherent with seepage in crack essentially. And the material flowing should accord with the relative hydraulics formula. Based on some hydraulics formula deduced by scholar at home and abroad, the thesis deduces and establishes the infiltrating model of grout in the plane and declining crack after considering that the grout is belong to Bingham fluid and has stream nucleus when it flows.The applied research of projection has manifested that the technics of grouting in fractured rock mass with grout is similar to others. But the grout is adapted the method of third class stirring and the method of major cycle in grouting. The injection rate and formulation should be controlled and adjusted in accordance with practical situation to obtain the optimal effect.

  • 【网络出版投稿人】 中南大学
  • 【网络出版年期】2008年 05期
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