地下室抗浮设防水位标高取值的讨论以及抗浮措施

Discussion on the Value of Basement’s Anti-Floating Water Level Elevation and the Anti-Floating Measures

地下水勘察是岩土工程勘察的一项重要任务。近年来,带有深基坑的高层建筑和地下广场式建筑大量兴建,一旦地下水高于地下室基础底板时,必须提供合理的抗浮设计水位。因此,抗浮水位的合理确定会直接涉及到工程的安全性和成本问题,而实际中抗浮水位情况是比较复杂的,抗浮水位的标高取值尤其对一些水位变化大的地方,一直是地下水勘察的难点。抗浮水位取高了则造成浪费,估算低了则容易出事故,危险性很大。本文结合不同地貌地质和水文地质等条件探讨并总结了如何合理确定地下室的抗浮水位以及相应抗浮措施,运用工程实例区别于传统的“拉压抗浮”设计方法,倡导节能绿色技术以“疏”代“抗”的疏水降压方法及时降低地下水位以满足地下室抗浮要求。研究成果为相应的勘察与设计、施工单位确定抗浮水位或抗浮措施提供参考依据。

Groundwater survey is an important task in geotechnical engineering investigations. In recent years,a large number of high-rise buildings and underground square buildings with deep foundation pits have been built. Considering the groundwater is probably higher than the basement foundation floor,it is necessary to provide a reasonable anti-floating design water level. Therefore,the reasonable determination of anti-floating water level is directly related to the safety and cost of the project. In practice,the situation of anti-floating water level is relatively complex. The elevation of anti-floating water level,especially at some places where the water level changes greatly,has been a problem in groundwater survey. If the anti-floating water level is higher,it will cause waste,and if the estimation is lower,it can lead to accidents,which is very dangerous. Based on different geomorphological and hydrogeological conditions,this paper discusses and summarizes how to reasonably determine the anti-floating water level of basements and choose corresponding anti-floating measures. Using engineering examples,the proposed approach is different from the traditional “tension,compression and anti-floating” design method. It advocates that energy-saving green technology should replace the “anti-floating” with “sparse” water-drainage and pressure-lowering method and timely lowering groundwater level to meet the anti-floating requirements of basements. It provides a reference for the corresponding survey and design,construction institutes to determine the anti-floating water level or anti-floating measures.