粉喷桩联合土工格栅加固桥台软基理论及工程应用

发布时间：2018-06-04 10:55

本文选题：粉喷桩 + 土工格栅　；参考：《湖北工业大学》2014年硕士论文

【摘要】：随着我国高速公路建设的进一步发展，投入运营的高速公路出现的各种各样隐患也越来越多。其中桥头跳车是目前公路建设中最常见的通病之一，严重影响了行车舒适性，降低了车辆的行驶速度和道路的通行能力。黄鄂高速公路部分路段存在着软土地区，为了确保公路在投入运营后的安全正常使用，需要对软土路段，，尤其是桥涵构造物台背的软基进行特殊处理。论文对公路桥头跳车防治技术进行了总结研究，给出了各种桥头处理方法的适用性，为工程中桥头的不同地质情况提供了一定的理论依据。同时依托实际工程中采用粉喷桩联合土工格栅的综合处置技术处理桥头过渡段的软基方法，针对施工的工期紧、地基土性质差具有很好的效果。基于工程实际意义，论文对路桥衔接段的差异沉降机理以及桩网的受力特性进行了分析，对处理桥头软基、防止桥头跳车病害具有一定的指导意义。首先，分析了桥头与路堤接洽处沉降差异的原因及差异机理，总结了现行桥头与路堤接洽处沉降差异的防治措施：地基处治技术、反开挖填贫混凝土、预抛高处理法、土工格栅处治台背填土、路面处置技术、排水固结法以及综合处置技术。其次，依据土拱效应分析了桩及其加筋后桩体的受力机理，并分别与Hewlett模型试验和Kempfertt的模型试验结果进行对比，得出该论文提出的桩体的受力计算方法是合理的。第三，介绍了路桥搭接处差异沉降控制技术—粉喷桩联合土工格栅技术。该方法采用槽钢或U型钉将筋材与邻近的钢筋混凝土结构物组成为一个较为牢靠的固定体系，其独特的结构特性，可以减小路堤的侧向位移和路桥刚柔过渡处的不均匀沉降，提高路堤的整体稳定性和增加桩体荷载分担比。最后，对粉喷桩联合土工格栅的加固桥头软基的现场试验进行研究。主要研究的内容是对实际工程中的桥头过渡段软基采用水泥粉喷桩处理后，针对加筋和未加筋的填方路堤产生的沉降、位移以及土压力的监测数据进行了对比分析，验证了粉喷桩联合土工格栅能有效减小路堤沉降和不均匀沉降。
[Abstract]:With the further development of highway construction in our country, there are more and more hidden dangers of expressway put into operation. The bridge-head jumping is one of the most common problems in highway construction, which seriously affects the driving comfort, reduces the speed of the vehicle and the capacity of the road. There are soft soil areas in some sections of Huang-E Expressway. In order to ensure the safe and normal use of the highway after putting into operation, special treatment is needed for the soft soil sections, especially for the soft foundation at the back of the bridge and culvert structure. The paper summarizes and studies the prevention and cure technology of highway bridgehead jumping, and gives the applicability of various bridge head treatment methods, which provides a certain theoretical basis for different geological conditions of bridge head in engineering. At the same time, the soft foundation method of bridge head transition section is treated by the comprehensive disposal technology of powder jet pile combined with geogrid in the actual project. In view of the short construction period and the poor properties of foundation soil, it has a good effect. Based on the practical engineering significance, the paper analyzes the differential settlement mechanism of the road and bridge connection section and the mechanical characteristics of the pile net, which has certain guiding significance for the treatment of the soft foundation at the bridge head and the prevention of the bridge head jumping disease. Firstly, the causes and mechanism of the settlement difference between the bridge head and the embankment are analyzed, and the prevention and treatment measures of the settlement difference between the bridge head and the embankment are summarized: the foundation treatment technology, the anti-excavation filling poor concrete method, the pre-throwing treatment method, the prevention and treatment measures of the settlement difference between the bridge head and the embankment are summarized. Geogrid treatment platform backfill, pavement disposal technology, drainage consolidation method and comprehensive treatment technology. Secondly, according to the soil arch effect, the stress mechanism of the pile and its reinforced pile is analyzed, and compared with the results of Hewlett model test and Kempfertt model test, it is concluded that the method proposed in this paper is reasonable. Thirdly, it introduces the differential settlement control technology of road and bridge lap-powder jet pile combined with geogrid technology. The method uses channel steel or U type nail to form a solid fixed system between steel bars and adjacent reinforced concrete structures. Its unique structural characteristics can reduce the lateral displacement of embankment and the uneven settlement in rigid and flexible transition of roadway and bridge. Improve the overall stability of embankment and increase the load sharing ratio of pile. Finally, the field test of cement-jet pile combined with geogrid to strengthen soft foundation at bridge head is studied. The main content of this paper is to compare and analyze the monitoring data of settlement, displacement and earth pressure caused by reinforced and unreinforced embankment after the soft foundation of bridge head transition section is treated with cement powder jet pile. It is proved that the combination of powder jet pile and geogrid can effectively reduce the settlement of embankment and uneven settlement.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1;U445.7

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