许多城市的高层建筑施工都需开挖深度较大的基坑,给施工带来很多困难,尤其在软土地区或城市建筑物密集地区。施工场地邻近的已有建筑物、道路、纵横交错的地下管线等对沉降和位移很敏感,不允许采用较经济的放坡开挖,而需在人工支护条件下进行基坑开挖。支护结构如何选型、进行合理的布置和设计,这些会直接影响如何组织施工,以及施工过程中的支护结构监测和环境保护等问题。支护结构的设计和施工,影响因素众多,如土层种类及其物理力学性能、地下水情况、周围形境、施工条件和施工方法、气候等因素都对支护结构产生影响;再加上荷载取值的精确性和计算理论方面存在的问题,要想使支护结构的设计完全符合客观实际,目前还存在一定的困难。为此,虽然支护结构多数都属于施工期间挡土、挡水、保护环境等所用的临时结构,但其设计要在保证施工安全的前提下,尽力做到经济合理和便于施工。 Many cities have to excavate deep foundation pit for high-rise building construction, which brings many difficulties for construction, especially in the soft soil areas or urban buildings. The existing buildings, roads and underground pipelines in the vicinity of the construction site are very sensitive to the settlement and displacement. Excavating the more economical grading and excavation, excavation of the foundation pit under artificial support is required. How to select the type of support structure, reasonable layout and design, which will have a direct impact on how to organize the construction, as well as the construction process of support structure monitoring and environmental protection and other issues. The design and construction of support structure have many influencing factors, such as the type of soil and its physical and mechanical properties, groundwater conditions, surrounding environment, construction conditions and construction methods, climate and other factors have an impact on the support structure; together with the load The accuracy of the value and calculation of the theoretical problems, in order to make the support structure design fully in line with the objective reality, there are still some difficulties. For this reason, although most of the support structures belong to the temporary structures used for retaining earth, retaining water and protecting the environment during the construction period, their design should try their best to be economical and convenient for construction under the premise of ensuring construction safety.