【作者】 王建州；

【导师】 周国庆； 刘志强；

【作者基本信息】 中国矿业大学 ， 岩土工程， 2008， 博士

【摘要】 煤炭作为我国重要的一次能源,在能源结构中仍然占有十分重要的比重;随着浅层煤炭资源的开采殆尽,为满足国民经济发展对煤炭资源的需求,深部煤炭资源开采的需求已经日益迫切。预计未来10年内我国东部地区将新建井筒100个以上,这些井筒都不可避免地要穿过深厚的表土层(400~800m);随着冻结深度和表土层厚度的不断增加,冻结壁的厚度也不断增大(冻结壁的厚度已经由最初的3m左右,增加到目前10m以上,与井筒的开挖荒径相当),冻结壁形成也由一圈冻结增加到双圈和三圈冻结,但是对于多圈形成厚冻结壁,仍然按照“冻结壁的平均温度”将冻结壁假设为均质的材料来研究,势必存在着一定误差,因此,有必要开展深入的研究。本文采用大型物理模拟试验、数值模拟、理论分析等综合研究手段,开展了“深厚表土层非均质厚冻结壁力学特性研究”,研究内容考虑了深厚表土层特殊的工程条件和冻结凿井工程特点,采用“深土冻土力学”的研究方法,获得了多圈冻结形成的非均质厚冻结壁的力学特性。本文多种研究手段相互印证,证明了研究成果的可靠性。论文以粘弹塑性理论为基础,考虑深厚表土层中多圈冻结管形成的厚冻结壁径向温度的分布,在试验和实测的蠕变方程的基础上,研究了冻结壁径向非均质条件下,冻结壁的应力场、承载性能和径向变形规律,依据本文提出的“分层理论模型”应用于多圈形成的厚冻结壁计算,较“平均温度”更加合理和科学;同时研究了有限段高条件下,考虑工作面上下端不同约束条件时,冻结壁的径向变形解析解,并讨论了该公式的应用范围,为冻结壁设计提供了有益参考。采用ANSYS有限元分析软件模拟了深厚表土层多圈冻结冻结壁的温度场演变规律,在数值模拟温度场的基础上,采用间接耦合分析了非均质厚冻结壁的应力场和变形场的规律。文中讨论了不同约束条件和开挖段高对于冻结壁径向变形的影响;开展了冻结砂土和冻结黏土分层的数值模拟研究,初步探讨了砂土层和黏土层组合层影响下冻结壁的稳定性。自行设计、研制了深部非均质厚冻结壁模拟试验系统,该系统可以模拟深度400~800m范围内,多圈冻结管形成的冻结壁的温度场和冻结壁整体变形规律,本文模拟试验的过程按照:固结——有压冻结——开挖卸载(蠕变)进行,符合冻结法凿井特殊施工力学行为特点。在理论分析、数值模拟、物理模拟和工程实测的基础上,提出了深厚表土层多圈冻结厚冻结壁设计模型,模型考虑了冻结壁径向温度不均匀的影响,为深厚表土层中冻结壁的设计奠定了理论基础。课题研究具有重要的经济价值和社会价值。更多还原

【Abstract】 Coal is the primary energy in China, in order to satisfy the development of national economy, the needs of coal resource under the deep alluvium become more and more impendent. And these shaft well are inevitably needed through the deep alluvium (400~800m). With the increasing freezing depth and topsoil layer depth, the depth of the frozen wall also increased constantly. But the thick frozen wall formed by multi-coil frozen pipes is still researched as homogeneous material according to the average temperature of frozen wall, there may be some error that may affect the safety of the frozen wall in the deep alluvium.By the physical simulation, numerical simulation and theoretical analysis, as well as the data of engineering measuring, the research on mechanical characteristic of multi-coil thick frozen wall in deep alluvium has been taking on. Combining the condition of deep alluvium and the engineering characteristic of freezing shaft are also taken into consideration, as well as the effect of the heterogeneity of multi-coil thick frozen wall for its stability, the engineering properties of the frozen wall in non-uniform temperature field under high confining pressure had been carried out.The second chapter is based on the elastic-plastic theory, and considering radial delamination of multi-coil thick frozen wall in deep alluvium (radial temperature distributing of frozen wall). On the basis of constitutive relation of deep frozen soil in test measuring, the stress field, carrying capacity and radial deformation characteristic of frozen wall have been researched under the condition of the radial uneven condition. Meanwhile basing on the measured data, the rule of radial distortion was researched, considering the upper and lower side of the working face at different constraints above the limited segment height conditions, so, some references were provided to the design of frozen wall in deep alluvium.The evolution law of temperature field of the multi-coil thick frozen wall in deep alluvium along with the stability of the frozen wall in the direction of the depth of the different layers (layers of sand and clay) were simulated by ANASYS (finite element analysis software), taking on the premise of non-uniform temperature field of the frozen wall into account, to obtain more accurate distribution law of stress field and deformation field, which can provide a useful reference to the design and construction for freezing shaft in deep alluvium.The success of the design and establishment of deep soil and frozen soil multi-purpose simulation systems, and the physical simulation tests of multi-coil thick frozen pipes were carried through the test-bed. At the same time theoretical analysis and numerical simulation results correspond to each other.On the basis of theoretic analysis, numerical simulation, physical simulation and engineering measured the deep alluvium in thick multi- coil wall to freeze time and space design was brought out for multi-coil thick frozen wall of the deep alluvium. This research had important economic value and social value.更多还原