坡桩支护基坑开挖对邻近船闸的影响研究

发布时间：2018-04-20 23:03

本文选题：船闸 + 基坑开挖　；参考：《长沙理工大学》2015年硕士论文

【摘要】：近年来,随着我国腹地经济和沿江产业的快速发展,内河航运升级的需求日益急迫。目前,国内外主要采用梯级渠化与航道整治相结合的方式升级航道,在原有航运枢纽基础上扩建高等级船闸是其中的方式之一。新建船闸闸址一般距离已建船闸较近,工程施工采用基坑临时支护开挖的方式。邻近船闸基坑开挖工程除具有基坑工程的一般特性外,还具有其自身明显的特点。本文着力于邻近船闸基坑开挖工程的特殊性及目前相关研究成果相对缺乏的现状,采用土工模型试验及数值仿真计算相结合的研究手段,以某航运枢纽衡重式闸室结构段邻近基坑开挖工程为背景,对坡桩联合支护型式(简称坡桩支护)基坑开挖过程中的支护效果、工作机理及相应的影响因素展开了研究,并与常见的排桩支护型式进行了比较,主要的研究成果及结论如下:(1)邻近船闸基坑开挖分别采用坡桩支护和排桩支护时,基坑开挖完成时前者支护和邻近闸墙顶端的水平位移值均小于后者,表明当具备局部的放坡空间时,坡桩支护型式下邻近衡重式船闸结构基坑开挖的基坑支护效果要优于排桩支护。(2)坡桩支护型式由于是根据邻近船闸基坑工程的特点,结合了放坡开挖和排桩支护两种型式的优点而成的一种联合型的支护,其中采用局部放坡开挖的方式可以缩短支护结构的自由高度,增强支护结构的嵌固强度,而采用竖直开挖加排桩支护的方式可以解决基坑与邻近船闸之间距离不足的问题,从而形成了良好的基坑支护效果。(3)坡桩支护型式下基坑顶部放坡随着放坡起点距离船闸顶端距离的增大,闸墙结构向墙前倾斜的幅度随之增大,且随着距离的增大,影响效果逐渐减弱;随着放坡坡度逐渐放缓,闸墙结构向墙前倾斜的幅度相差不大。(4)基坑底部放坡开挖随着放坡坡度逐渐放缓,斜坡土体对基坑产生的嵌固作用逐渐增强,该开挖步内支护和闸墙结构由向坑内(或墙后)发生倾斜逐渐转为向坑外(或墙前)发生倾斜。(5)当船闸处于不同运行工况时,随着船闸内部水位的增大,支护和闸墙结构向坑内(或墙后)倾斜的幅度更大,表明船闸内部水位越高对基坑开挖工程的安全稳定越不利。
[Abstract]:In recent years, with the rapid development of the hinterland economy and industry along the Yangtze River, the demand of inland shipping upgrade is increasingly urgent. At present, at home and abroad, the combination of cascade canal and channel regulation is mainly used to upgrade the waterway, one of which is to expand the high-grade lock on the basis of the original shipping hub. The newly built lock site is generally close to the existing lock, and the temporary excavation of foundation pit is adopted in the engineering construction. In addition to the general characteristics of foundation pit engineering, the excavation engineering of adjacent lock also has its own obvious characteristics. This paper focuses on the particularity of excavation engineering of adjacent lock foundation pit and the relative lack of relative research results at present, and adopts the research means of combining geotechnical model test and numerical simulation calculation. Based on the excavation of the foundation pit adjacent to the structural section of the weighty sluice chamber of a shipping hub, the supporting effect, working mechanism and corresponding influencing factors during the excavation process of the slope pile combined support type (abbreviated as slope pile support) foundation pit are studied. The main research results and conclusions are as follows: (1) when excavation of foundation pit of adjacent lock adopts slope pile support and row pile support, When the excavation of foundation pit is completed, the horizontal displacement of the former support and the adjacent gate wall is smaller than that of the latter, which indicates that when there is local sloping space, Under the slope pile support type, the excavation effect of the foundation pit of the adjacent ship lock structure is better than that of the row pile support. 2) the slope pile support type is based on the characteristics of the foundation pit engineering of the adjacent ship lock. Combined with the advantages of two types of slope excavation and row pile support, a combined support is developed, in which the free height of the support structure can be shortened and the embedded strength of the support structure can be enhanced by using the method of partial slope excavation. The problem of insufficient distance between foundation pit and adjacent lock can be solved by vertical excavation plus row pile support. Thus, a good foundation pit support effect is formed. Under the slope pile support type, the slope at the top of the foundation pit increases with the distance from the starting point of the caving slope to the top of the lock, and the amplitude of the slanting of the gate wall structure to the front of the wall increases, and with the increase of the distance, The influence effect is gradually weakened, along with the slope of sloping slope gradually slowing down, the amplitude of slanting of sluice wall structure to the front of the wall is not different. 4) the slope excavation at the bottom of foundation pit gradually slows down, and the embedded effect of slope soil on the foundation pit increases gradually. The excavation step support and the structure of sluice wall are inclined gradually from inside (or behind the wall) to outside (or in front of the wall). When the lock is in different operating conditions, with the increase of the water level inside the lock, The slope of support and sluice wall structure to the pit (or behind the wall) is larger, which indicates that the higher the water level in the lock is, the less safe and stable the excavation works are.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U641

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