【作者】 杨光；

【导师】 王建有；

【作者基本信息】 郑州大学 ， 水工结构工程， 2012， 硕士

【摘要】 随着我国的经济发展和城市化加快,新建高层楼房如雨后春笋。由于土地规划、楼盘开发、资金周转不同步等原因,出现了在市区内密集建筑群中兴建基坑建设新楼的情况。基坑施工过程中将开挖土方暂时堆放在邻近建筑物旁是较为常见的现象。在没有科学规划与分析的情况下盲目堆放,极易造成附近建筑物与地下结构的破坏。在相关规范中未就建筑物附近堆载对建筑物稳定的影响这一方面做规定与说明。基坑工程相关规范中仅提到基坑边禁止堆土,未就禁止堆土的距离与堆土高度的标准作出说明,国内在相关领域研究也较少。建筑物附近堆载土体,楼房重力荷载对基坑支护的影响；基坑开挖、土方堆放单一条件下相邻已有建筑物所受影响；二者共同作用下建筑物基础的形变过程都有待进一步研究。本文使用ABAQUS有限元软件对基坑开挖及建筑物附近堆放土方的施工过程进行三维有限元模拟分析,进行的研究工作及得出的主要结论如下：1)在查阅大量文献资料,研究学习关于基坑工程对基坑外土体的影响、土方堆载对建筑物影响的多种常用计算方法的基础上,对某楼盘实际基坑工程进行三维有限元模拟,分析该工程的基坑在实际开挖工序下,将开挖土体堆放在已建楼房与基坑相对一侧对桩基础的影响,得出在距离已建楼房5m的地面堆载土体时的临界基坑开挖深度,开挖深度小于临界深度时可保证已建楼房的桩基础安全。2)通过有限元模拟,分析了以下三因素即不同深度基坑开挖、堆载土体不同高度、堆载与已建楼房距离分别对已建楼房桩基础的影响,尤其是桩基础的形变性状,得出了单因素对已建楼房桩基础影响的规律。3)分析了在基坑开挖和堆载共同作用下的楼房桩基础位移规律,并得出在开挖深度不同情况下的堆载安全距离与堆土高度,以求对工程实际提供参考。4)提出了减小堆载对附近建筑物影响的两种方案：通过增大已建建筑物附近堆载土体底面积而降低堆载土体高度；增加支护结构排桩数。对两种方案进行验证,证明两方案均能有效减小堆载对桩基础的影响。更多还原

【Abstract】 With the economic development and the urbanization of our country, newly built high buildings are springing up in the urban areas. As the development planning, cash flow and estate development are not synchronized, and other reasons, many foundation pits are excavated among dense high buildings. During the process of excavation, the removed earth placed beside the buildings nearby is a common phenomenon. Aimlessly removed earth without scientific planning and analysis can easily result in the destruction of nearby buildings and underground structures. The impacts of the removed earth placed beside the nearby buildings are not specified in any relevant regulations. Some related regulations mention that removed earth placed beside the foundation pit is prohibited, but there is not any specification in terms of its distance from its nearby buildings and the height of the removed earth. The research in this field is far from enough. Further studies should be carried out in the aspects of removed earth laced beside buildings, the impact of building gravity loads on excavation support, foundation excavation, the influence of removed earth piled on its surrounding buildings, and the impacts of both the removed earth and the buildings themselves on the deformation process of the building foundation.The software ABAQUS is used in this thesis to make the three-dimensional finite element simulation analysis on the construction process of excavation and bulldozers. The main research work and the conclusions of this thesis are as follows:1) Based on reviewing related literature and the studying of various calculation methods in terms of the impact of the excavation on the soil outside the pit, and the removed earth placed besides surrounding buildings, the author makes a three-dimensional finite element simulation on a real estate foundation pit. After the analysis of the impacts of the removed earth placed at the opposite side of nearby buildings on the building foundation, the author figures out the depth of the foundation pit, which can guarantee the safety of the building foundation, under the condition that the removed earth is placed five meters away from its nearby buildings.2) The finite element simulation analysis is adopted to analyze the impacts of three factors on the pile foundation of existing buildings respectively. These three factors are the excavation of different depths of foundation pits, different heights of removed earth, and the distance between existing buildings and removed earth.3) The author analyzes the impacts of both foundation pit excavation and removed earth beside the deformation of building foundation, and figures out the appropriate distance between the removed earth and its surrounding buildings and the appropriate heights of removed earth under the condition of different depths of excavation.4) Two programs are provided in this thesis to reduce the impacts of the removed earth on its surrounding buildings:to lower the height of the removed earth by enlarge its basal area, and to strengthen the supporting structure. In addition, the efficiency of these two programs are verified and it turns out to be effective in reducing the impacts of the piling earth on its surrounding buildings.更多还原