基于分形理论的坝基裂隙岩体注灰量与导水率关系研究

发布时间：2019-01-12 18:57

【摘要】：由于天然岩体裂隙分布的隐蔽性和不确定性,很难准确评价天然裂隙岩体的渗透性和可灌性。离散裂隙网络作为描述天然裂隙网络的有力工具,能在一定程度上反应裂隙岩体的某些特征,但都是基于统计意义上的概率分布,无法反应裂隙网络参数的内部联系以及微观特征。Mandelbrot提出的分形几何是描述不规则物体的重要工具,研究发现裂隙网络中的裂隙迹长分布服从分形特征,很多学者利用这一理论对裂隙网络的渗透性进行了研究,推导了裂隙网络渗透系数的表达式。然而缺乏裂隙网络的可灌性和灌浆量的研究。本文首先利用裂隙网络的分形特征和裂隙迹长与隙宽的关系,建立了裂隙岩体导水率的分形模型,推导了裂隙岩体导水率与分形维数的关系表达式,并与已有研究结果进行了对比,证实了该关系式的可靠性。其次,分析了裂隙岩体灌浆注灰量与分形维数的关系,进而推导了注灰量与导水率的关系式,根据注灰量与导水率的关系曲线对灌浆区域的划分,定义了3个不同的灌浆区域:正常区域、微小裂隙区域和扩展区域,分别对应于正常灌浆、微小裂隙较多和裂隙扩展变形这3种不同的灌浆状态。最后,通过与工程实测数据的对比,证实了本文注灰量与导水率关系式的可靠性和适用性,也说明了3个灌浆区域的划分是合理并且重要的。因此,该关系式和灌浆区域的划分可以用来预测和评价实际工程灌浆施工的合理性和可灌性。
[Abstract]:Due to the invisibility and uncertainty of the distribution of fractures in natural rock mass, it is difficult to accurately evaluate the permeability and irrigability of natural fractured rock mass. As a powerful tool to describe natural fracture network, discrete fracture network can reflect some characteristics of fractured rock mass to some extent, but it is based on statistical probability distribution. The fractal geometry proposed by Mandelbrot is an important tool to describe irregular objects. Many scholars use this theory to study the permeability of fracture network and derive the expression of permeability coefficient of fracture network. However, there is a lack of research on the irrigation capacity and grouting quantity of the fissure network. In this paper, the fractal model of the hydraulic conductivity of fractured rock mass is established by using the fractal characteristics of fracture network and the relationship between crack trace length and gap width, and the expression of the relation between hydraulic conductivity and fractal dimension of fractured rock mass is derived. The reliability of the relationship is confirmed by comparing with the existing research results. Secondly, the relationship between grouting ash quantity and fractal dimension of fractured rock mass is analyzed, and the relationship between ash injection quantity and water conductivity is deduced, and the grouting area is divided according to the relationship curve between ash injection quantity and water conductivity. Three different grouting regions are defined: normal area, small fissure area and extension area, which correspond to three different grouting states respectively: normal grouting, large number of small cracks and crack spreading deformation. Finally, the reliability and applicability of the relationship between the ash injection rate and the water conductivity are confirmed by comparing with the measured data, and the division of the three grouting areas is reasonable and important. Therefore, the relationship and the division of grouting area can be used to predict and evaluate the rationality and irrigability of actual grouting construction.
【作者单位】： 天津大学水利工程仿真与安全国家重点实验室;
【基金】：国家自然科学基金(51439005);国家自然科学基金(51339003) 国家重点基础研究发展计划(973计划)(2013CB035904)
【分类号】：TV223
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本文编号：2408092