复杂地质条件下桩基施工关键技术研究

发布时间：2018-05-13 13:20

本文选题：钻孔灌注桩 + 溶洞　；参考：《武汉工程大学》2015年硕士论文

【摘要】：随着我国城市化进程的逐年加快,车辆大幅度增加,城市道路中普通平交路口的通行方式已经不满足现代社会的发展需求,立体高架桥越来越多的出现在我国城市中。然而,由于各个城市的地理位置不同,所处的地质条件也千差万别。在已有的城市高架桥实施过程中,经常会遇到各种复杂的地质条件,使得高架桥的施工往往面临着很多难题,溶洞便是其中最为复杂的一种。本文通过实践与研究,总结出了一套成形的复杂地质条件(溶洞)下城市高架桥的施工关键技术,为后续的城市高架桥施工建设提供了有益的参考。由于岩溶的地貌特征破坏了工程地质条件的连续性,使得岩溶地层钻孔灌注桩的施工尤其困难。在通常的情况下,岩溶地层中的溶蚀、沟槽或溶洞,大多是呈水平方向发育的,它们的规模大小不同,形态各异,并且其断面的走势高低不同,宽窄不一,且多支洞;当岩溶发育完善时,钻孔灌注桩的施工是最难以掌控的。文章针对不同类型溶洞,一方面,采取抛填黏土或片石、止水帷幕或分层预注浆、钢护筒跟进等不同的技术处理措施,可以有效地解决岩溶地质条件下钻孔过程中易塌孔的难题,从而提高桩基的一次成孔率,节约成本,确保桩基施工质量;另一方面,传统的破桩头施工工艺需在混凝土强度达到70%方可施工。本文推荐的整体提升破桩头施工方法,即不需要等待桩身混凝土强度达到70%,在早期便将桩头切除,这种技术本身对桩身的完整性并没有影响,而且能减少施工时间,缩短工期。由于我国国土面积较大,各地区的地质条件不一样,因而各地方施工存在着各自不同的问题,尚无法形成一套全国通用的复杂条件下城市高架桥的施工关键技术,对其他复杂地质条件下的桩基施工,仍需继续探索和研究。
[Abstract]:With the acceleration of urbanization in our country, the number of vehicles increases greatly. The traffic mode of the ordinary intersection in urban roads has not met the development needs of modern society, and more stereoscopic viaducts appear in the cities of our country. However, due to the geographical location of different cities, the geological conditions vary widely. During the implementation of the existing urban viaduct, various complicated geological conditions are often encountered, which make the construction of viaduct often face many difficulties, among which the karst cave is the most complex one. Through practice and research, this paper summarizes a set of key techniques for urban viaduct construction under complex geological conditions (caverns), which provides a useful reference for the subsequent construction of urban viaducts. Because the geomorphological features of karst destroy the continuity of engineering geological conditions, it is particularly difficult to construct bored piles in karst strata. In general, the dissolution, trench or cave in karst strata is developed in horizontal direction, their size and shape are different, and the trend of cross section is different, width and narrow, and many holes; When karst is well developed, the construction of bored pile is the most difficult to control. For different types of caverns, on the one hand, different technical treatment measures are taken, such as throwing clay or flake stone, sealing curtain or stratified pre-grouting, following up with steel tube, etc. It can effectively solve the difficult problem of easily collapsing holes in the process of drilling under karst geological conditions, thus increasing the primary porosity of pile foundation, saving cost and ensuring the construction quality of pile foundation, on the other hand, The traditional construction technology of broken pile head needs to reach 70% concrete strength before construction. The construction method of integral lifting broken pile head recommended in this paper is that the pile head is cut off at the early stage without waiting for the concrete strength of pile body to reach 70. This technique itself has no effect on the integrity of pile body and can reduce the construction time and shorten the construction period. Due to the large area of our country and the different geological conditions in different regions, there are different problems in the construction of each place, so it is not possible to form a set of key techniques for the construction of urban viaducts under the complex conditions commonly used in the whole country. It is necessary to continue to explore and study the pile foundation construction under other complicated geological conditions.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753.3

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