基坑开挖对邻近建筑物的影响及加固处理

The influence and reinforcement of foundation excavation on nearby building

以重庆市电信综合楼为例,通过对不同部位裂缝、地基基础及倾斜情况的检测,对基坑开挖导致邻近建筑物 异常进行了成因分析.该综合楼地基基础不均匀沉降产生的主要外因是邻近拟建新项目工程大面积基坑开挖、大量 抽取地下水,改变了地基的土体应力状态,导致周边土体重新固结沉降.内因是平面刚度变化不均匀,空间刚度也较 差,抵抗不均匀沉降的能力较弱,场地地基欠密实,部分充水严重,虽然采取筏板基础处理,但建筑仍易受地基环境 变化的影响.最后,提出了综合加固整改措施并实际实施：通过对地基基础进行压力灌浆及髙压旋喷灌注粧加固处 理、底部框架结构增设钢筋混凝土斜支撑、上部砌体结构增设拉梁及构造柱等加固整改.

Aiming at the abnormal phenomena of a telecom comprehensive building in Chongqing city, detected the different parts of the crack, foundation and slope, we have studied the building abnormal phenomenon resulted from foundation pit excavation. The uneven settlement of foundation was caused by great two factors, some new projects^ excavation of foundation pits in large scale and the overuse of groundwater. They have changed the foundation^ stress state in soil, this change of stress state make soil renew to consolidate and collapse. With uneven change of flat stiffness, inferior of the space stiffness, weak resistance to uneven settlement, insufficient density of the foundation, immersion of some parts, the building is affected by the foundation, although its foundation was tamped by wood block. Finally, the paper has proposed rectification measures of integrated strengthening-to strengthen and rectify by offering pressure grouting and high pressure jet grouting piles for foundation, adding reinforced concrete to prop up the bottom frame structure and adding straining beam and constructional column for the upper masonry structure.