桩基对进水塔塔基动力稳定性影响研究

进水塔是水利工程的重要组成部分,具有塔身高、塔壁薄等特点,在地震工况下容易发生结构失稳破坏。针对进水塔地震工况下抗滑抗倾覆能力差的问题,提出加设灌注桩的方法提高塔基的动力稳定性,并以甘肃省某引水工程进水塔为例,采用有限单元法,从桩基对进水塔塔体应力、桩基受到的剪力和弯矩及地基位移分布情况三个方面分析灌注桩对进水塔塔基动力稳定性的影响。分析得到:加设灌注桩可降低塔体中下部的应力值,并改善该处的应力分布;塔基高程处的灌注桩所受到的剪力和弯矩较小;加设灌注桩后,塔底附近的位移量值有所减小,且没有出现明显的潜在滑移圆弧面。说明设置桩基加固进水塔地基的措施提高了进水塔地基的动力稳定性。

Influence of Pile Foundation on Dynamic Stability of Intake Tower Foundation

The intake tower with characteristics of tall tower body and thin wall is an important part of water conservancy project. It easily suffers structural instability and damage under earthquake. In view of the poor anti-sliding and anti-overturning ability of intake tower, the method of setting cast-in-place piles was proposed to improve the dynamic stability of tower foundation in this paper. Taking the intake tower of a water diversion project in Gansu Province as an example, the influence of cast-in-place piles on the dynamic stability of intake tower foundation was analyzed from three aspects: the stress of intake tower body from pile foundation, the shear force and bending moment of pile foundation, and the distribution of foundation displacement. The results showed that the cast-in-place piles can reduce the stress value at the middle and lower part of tower and improve the stress distribution; besides, after adding cast-in-place piles, the displacement value near the tower bottom decreases and there is no obvious potential slip arc surface. In conclusion, the dynamic stability of intake tower foundation is improved by setting pile foundation.