摘要
滑坡是一种多发又常能造成极大危害的斜坡地质灾害,我国西部山区又是滑坡的多发区,因此做好有关滑坡的研究防治工作一直倍受关注。在滑坡防治工程中抗滑桩的应用最为广泛,预应力锚索抗滑桩是随着锚索在工程上的应用而产生的一种新型支挡结构,相对于普通抗滑桩,其受力状态更加合理,并且可以有效的控制桩身的位移和相应的应力分布,所以出现后就得到了非常广泛的应用。但是,由于桩锚体系与滑坡体之间的相互作用机理非常复杂,所以,对预应力锚索抗滑桩的作用机理的研究还需要进一步深入的探索,系统结构的力学计算模型、计算方法以及工程应用还有待进一步完善。
论文对桩、锚、土之间相互作用之间的研究成果进行了分析总结,对现有文献中预应力锚索抗滑桩支挡结构的力学模型中的桩锚变形协调等问题进行分析和总结,并建立合理的力学计算模型。另外,研究了预应力锚索抗滑桩的结构设计,在对所建立的预应力锚索抗滑桩力学计算模型进行求解时,引用相对成熟的计算方法,并采用较成熟的结构设计方法进行结构设计。采用Visual C++进行程序开发,完成预应力锚索抗滑桩的结构计算及结构设计,并自动绘制施工图。
通过研究总结,论文取得以下结论和成果。
1分析了现有文献中存在的几种桩锚协调变形条件,在考虑了预应力施加过程中桩已经变形,对桩锚协调变形条件进行了改进,并建立协调变形方程。改进后的模型更符合桩、锚实际受力情况。
2通过文献分析总结得出,预加固力仅仅限制了预应力施加阶段桩身的变形,对桩身稳定阶段的力学计算模型影响不大,滑坡推力可不折减。
3基于桩锚协同作用,改进了预应力锚索抗滑桩力学计算模型。运用传统的计算方法,对改进的预应力锚索抗滑桩的弹性桩和刚性桩力学模型进行求解,并推导出锚索预应力值或拉力值的公式。
4利用Visual C++平台进行程序编写,采用矩阵分析法和有限差分法两种算法,最终实现对本文采用的预应力锚索抗滑桩计算模型的力学计算,并自动生成弯矩、剪力和桩身的位移图,第三,进行桩身配筋设计和锚索结构设计,并自动成图。
5进行工程实例对比,结果显示,因考虑桩、锚受力的协调,降低了桩、锚承载力设计值,从而有效的节约了工程投资。
Landslide is a kind of slope geologic hazard which usually occur and cause extremely damage. Concerned it’s usually happened in country’s western mountain area, the research work about landslide’s prevention and control must be done. The anti-slide pile become widest application in the landslide prevention and control project. Compare with common anti-slide piles, the prestressed anchor cable anti-slide pile, which is the new type retain structure come into use by the project application of anchor cable, have more logical strained condition and can effective control pile body’s displacement with relevant stress distribution, and get extensive application. But because of the complicacy of interrelations between anchor-pile structure and landslide mass, the research about the prestressed anchor cable anti-slide pile’s mechanism of action still under exploration stage, and it’s mechanics computation model、computing method and project application still need to further improve.
In this article, the author made analysis and summary for the interrelation among piles, anchors and soil body, probe into the problems about pile-anchor structure’s compatible distortion which exist in the present prestressed anchor cable anti-slide pile’s mechanics model, and also tried to build reasonable mechanics computation model. Then the author made research about the present prestressed anchor cable anti-slide pile’s design, used developed computing method to solve the built mechanics computation model, and also used developed structure design method to finish the structure design. Finally the author used Visual C++ to develop the program, to complete the present prestressed anchor cable anti-slide pile’s structural calculation and structure design, and automatic made the contract drawing.
Through the research and summarize, the thesis got some conclusions and achievements which shows below:
1 After analysis some of pile-anchor structure integrate reconfiguration factors in the existing literature, and considered the pile had already deformation when the prestressing force working, the author developed the pile-anchor structure deformation factors and built the integrate deformation equations. The improved models more fit for the piles and anchor’s real force situation;
2 From the literature analysis, the author summarized that the pre-reinforcing force only limit the deformation which caused by the prestressing force to the stage pile body,and the force have no too much influence to the pile body stabilize stage’s mechanics computation model, the slide force don’t need require deduction;
3 The author improved the prestressed anchor cable anti-slide pile’s mechanics computation model based on the pile-anchor structure’s coordination effect. the author used the traditional computing method to try to solve the improved prestressed anchor cable anti-slide pile’s elastic pile and rigid pile mechanics model, and then derivate the anchor cable’s prestress amount or tension amount’s formula;
4 When use the Visual C++ to write the program, the author used two kinds of algorithm which are matrix analysis method and finite difference method, to finally achieve the mechanical calculation about the prestressed anchor cable anti-slide pile’s mechanics computation model which the author used in this thesis, and autogeneration the shift diagram about bending moment, shearing force and pile body, finally the author was running the design about pile body reinforcing bars and anchor- chain structure, and automatic mapping;
5 At final stage, the author made case history comparing, as result, because the anchor cable was concerned the pile and anchor’s stress coordinate and then reduced the pile and anchor’s bearing capacity design value, the project investment was effective economized.
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