【作者】 任彦龙；

【导师】 杨维好；

【作者基本信息】 中国矿业大学 ， 岩土工程， 2009， 博士

【摘要】 随着井筒所受围压的加大,井壁厚度越来越厚,如何经济合理地减薄井壁已成为目前冻结凿井法急待研究的关键技术之一。针对现行的单层井壁结构和施工工艺不能合理发挥井壁外侧区域的承载力问题,本文提出径向可缩新型井壁结构,采用理论分析、数值计算、物理模拟等方法研究了其力学特性和设计理论。着重运用理论分析方法,研究了径向可缩新型井壁结构和“分次砌筑,分步受力”井壁施工新工艺对提高井壁极限承载力作用。通过数值计算和物理模拟对理论分析结果进行了验证。最后以一个井筒为原型,对各种井壁结构设计方案进行了设计计算。本论文的主要创新点和贡献如下:1)提出了两种径向可缩新型井壁结构,研究结果表明:跟相同材料和厚度的单层井壁相比,径向可缩的新型井壁能提高井壁的承载力25%以上。2)提出了“先施工外层筒,待其承受设定的外载后施工内层筒,与外层筒共同受力”施工新工艺。通过理论推导出了新的施工工艺条件下井壁弹性和塑性应力和位移解。研究结果表明:新的施工工艺一般可提高井壁承载力25%以上。3)选用过——王(G-W)五参数强度准则,通过理论分析,获得了内、外层筒材料相同和内、外半径比相同的条件下,径向可缩井壁及“分次砌筑,分步受力”条件下双层井壁极限承载力的理论计算公式,为合理设计径向可缩井壁及井壁分层施工提供了理论依据。通过数值计算和物理模拟,对比了单层井壁、内钢板混凝土井壁和径向可缩井壁水平极限承载能力,验证了理论分析结果。4)提出了多轴应力作用下混凝土的强度提高系数K b计算方法,得到了K b值的变化规律和数值。研究表明,对于混凝土井壁,按多轴强度理论进行井壁验算更科学合理,有利于在掌握井壁总体安全度的前提下合理减薄井壁。5)针对所提出的井壁新结构和新工艺,提出了基于多层筒受力与变形规律的新型井壁设计理论与方法,为在保证井壁安全度的前提下合理利用井壁外侧区域的承载力提供了理论依据。更多还原

【Abstract】 Along with the shaft confining pressure increasing, the shaft lining is thicker and thicker. So how to make the shaft thinner economically and reasonably becomes one of the key technologies to be researched urgently. Currently monolayer shaft lining structure and construction technology can not reasonably exploit lateral capacity. For this question our study invented new radial compressible shaft lining structure. This paper studied its mechanical properties and design theory by theoretical analysis, numerical calculation and physical simulation methods. The paper focused on the affections of new radial compressible shaft lining and the new technology“batch-pouring, step-force”to improve horizontal ultimate bearing capacity by theoretical analysis. The theoretical analysis results were tested by theoretical analysis and numerical calculation. At last the different types of shaft lining design were calculated based on prototype of one shaft.The main innovations and contributions in the papers are as below:1) This paper invented two new types radial compressible shaft lining. Our results indicated that the new types radial compressible shaft lining can improved the bearing capacity more than 25% compared with monolayer shaft lining used the same material and thickness.2) This paper proposed the new construction technology. That is, we construct the outer shaft lining firstly. When it can bear the designed load we constructed the inner shaft lining which can bear the force with the outer shaft lining together. The paper deduced the elastic and plastic stress and displacement solution of shaft lining under the new construction technology. The results indicated that new construction technology can improved the bearing capacity of shaft lining more than 25%.3) Using G-W Failure Criteria, we derived the formulae to calculate the ultimate bearing capacity of radial compressible and double layer shaft lining of“batch-pouring, step-force”by theoretical derivation under same material and radius radio of inner and outer shaft lining. These results provide a theoretical basis for designing two kinds of shaft lining structure.4) This paper proposed the method to calculate the concrete strength increased coefficient Kb under multi-axial stress. And we got the variation rules and values of Kb. The results indicated that it is more scientific to calculate the bearing capacity of concrete shaft lining by multi-axial strength theory.5) The paper proposed the new design theory and method based on multi-shaft lining force and deformation rule for new shaft lining structure and technology which provide a theoretical basis for reasonably using the later bearing capacity of shaft lining under the promising of shaft lining safety.更多还原