【摘要】 邻近基坑的既有建筑物由于基坑开挖引起的土体位移作用而产生附加变形甚至造成严重损伤。双排桩作为一种刚度较大的隔离措施成为当前的研究热点。以北京某地铁深基坑邻近高层居民楼为实例,对双排桩的桩排距、冠梁连接、桩间土处理等关键设计参数进行了有针对性的优化。采用数值模拟计算和现场监测,对双排桩、桩后土体及高层建筑等组成的位移场进行了分析,并进一步总结了双排桩、桩后土体及高层建筑的变形规律。同时,通过双排桩与单排桩的变形对比分析,验证了双排桩对位移场的隔离效果明显,围护结构背后土体的水平位移由17 mm降低到8 mm,减少了53%。有效控制了既有建筑的损伤程度,居民楼的最终最大差异沉降为6.9 mm,角变量为0.33‰,确保了邻近基坑居民楼的使用安全。为后续类似工程提供了有益的参考。更多还原

【Abstract】 The existing buildings adjacent to a deep foundation pit will be damaged seriously or additionally deformed when the foundation pit is excavated, and it will lead to motion of soils. The double-row piles as one of shielding measures are studied.Based on a deep foundation pit adjacent to high buildings in Beijing, the key design parameters of double-row piles such as distance of row piles, distance of piles, link of top beam, and strength of soils between the piles are analyzed. Through the numerical simulation and in-situ monitoring, the displacement field grouped by the double-row piles, soils after the piles and high buildings is analyzed. The deformation laws of the double-row piles, soils after the piles and high buildings are concluded.At the same time, it is proved that the double-row piles can reduce the displacement field obviously by comparing the double-row piles to the single-row ones. The horizontal displacement of soils after the piles decreases from 17 mm to 8 mm,with a percent of about 53%. The maximum differential settlement of high buildings is 6.9 mm and the angle variance is 0.33‰.In a word, the safety of buildings is ensured by monitoring during the excavation of the deep foundation pit. It may be useful reference to the similar engineering in future.更多还原