沉陷区铁路线下开挖支护体系稳定性研究

发布时间：2018-04-22 16:54

本文选题：沉陷区 + 开挖支护体系　；参考：《中国矿业大学》2015年硕士论文

【摘要】：铁路运输是我国煤炭运输的主要途径。国内许多矿区的煤炭运输专线,由于其下方煤炭的开采,而随着地表变形发生了沉陷。由此导致涵洞被破坏以及被淹没在常水位下无法满足过水要求的后果,此时必须对涵洞进行改造重建。由于工程条件及各方面因素的限制,提出采用明挖法,以人工挖孔桩+内支撑对开挖支护体系进行支护,在桩顶架设临时架空体系保证正常通车的方法。在既有铁路线下进行涵洞改造,关键是为其提供满足施工需要的空间以及保证上部铁路的正常通行,开挖支护体系的稳定性直接影响了改造涵洞工程的可能性以及铁路的正常工作。本文在上述工程背景下,对沉陷区铁路线下进行开挖的情况进行了研究,主要内容和结论如下:首先,使用FLAC3D有限差分软件对沉陷区铁路线下开挖支护体系进行数值模拟计算,分析了开挖支护体系在不同的支护桩嵌固深度、开挖宽度、内支撑设置、列车荷载、分步开挖条件下支护桩的受力、变形及土体变形规律。结果表明上述因素均对支护桩的受力变形及土体变形造成不同程度的影响;基于以上研究结果,使用BP神经网络,采用数值模拟计算结果作为训练样本,尝试对开挖支护体系中支护桩在不同条件下的水平位移进行预测,结果表明神经网络预测结果与数值计算结果较接近,说明神经网络在开挖支护体系的计算中具有一定的适用性;最后,采用人工挖孔桩+内支撑实际工程中进行开挖支护效果明显,能够保证开挖支护体系的稳定及保证正常行车。而分别采用数值模拟计算和工程计算,两者在支护桩内力及变形的计算上结果相符,而在分析坑底隆起和地表变形量时,数值模拟的计算结果略小;在条件允许的情况下,应用两种方法进行计算,综合计算结果进行设计,才能取得更好的设计方案。
[Abstract]:Railway transportation is the main way of coal transportation in China. Because of the coal mining under the coal transportation line in many mining areas in China, subsidence occurs along with the surface deformation. As a result the culvert is destroyed and submerged under the constant water level which can not meet the requirement of overflowing. At this time the culvert must be rebuilt and rebuilt. Due to the limitation of engineering conditions and various factors, the method of using open excavation method to support the excavation support system with the support of manual excavated pile is put forward, and the temporary overhead system is set up on the top of the pile to ensure the normal opening to traffic. The key to the culvert reconstruction under the existing railway line is to provide it with space to meet the construction needs and to ensure the normal passage of the upper railway. The stability of excavation support system directly affects the possibility of culvert reconstruction and the normal work of railway. In this paper, the excavation of railway line in subsidence area is studied under the above engineering background. The main contents and conclusions are as follows: first, the numerical simulation of excavation and support system under railway line in subsidence area is carried out by using FLAC3D finite difference software. The stress, deformation and soil deformation of the excavation support system under the conditions of different embedded depth, excavation width, internal support setting, train load and step excavation are analyzed. The results show that all the above factors have different effects on the deformation of the supporting pile and the deformation of the soil, and based on the above research results, the BP neural network is used as the training sample, and the numerical simulation results are used as the training samples. This paper attempts to predict the horizontal displacement of supporting pile in excavation support system under different conditions. The results show that the prediction result of neural network is close to that of numerical calculation. It shows that the neural network has certain applicability in the calculation of excavation support system. Finally, the effect of excavation and support in practical engineering by manual digging pile is obvious, which can ensure the stability of excavation support system and guarantee the normal running of the excavation support system. The results of numerical simulation and engineering calculation are in good agreement with each other in the calculation of the internal force and deformation of the supporting pile, but the results of the numerical simulation are slightly smaller when analyzing the uplift of the pit bottom and the deformation of the surface. The better design scheme can be obtained by using two methods to calculate and synthesize the calculation results to carry on the design.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U449

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