华北某发电工程冷却塔地基处理设计

Design of foundation treatment of cooling tower in a power plant in northern China

华北某发电工程规划容量2×350 MW,冷却设备为2座加高型3 000 m2自然通风冷却塔,采用环板式基础型式,基底的平均压强可达220 kPa以上,环板基础坐落在粉质粘土层,承载力特征值为140 kPa,下卧层为粉土,承载力特征值为200 kPa。地面下20.00 m深度内存在饱和粉土层,初步判别在地震基本烈度为Ⅷ度时不液化,该场地土为Ⅱ类,土壤标准冻结深度为0.80 m,地震动峰值加速度为0.20 g,地下水位埋深8.00 m左右,对普通混凝土无腐蚀性,对钢结构及钢筋混凝土结构中钢筋具有弱腐蚀性。由于冷却塔所在位置原为养鱼池后改建为游泳池,受长期渗漏影响,基底土层普遍为软塑状态,属于中等至高压缩性土,不能满足天然地基的要求。经过技术经济比较,确定采用水泥粉煤灰桩复合地基。

A power plant in northern China has the installed capacity of 2 × 350 MW with two heightened 3 000 m2 natural draft cooling towers.The foundation type is ring flat-plate with the average pressure intensity at the foundation bottom of over 220 kPa.The ring flat-plate type foundation is located on silty clay layer with the bearing force of 140 kPa.The subjacent bed is silt with the bearing force value of 200 kPa.The saturated silt can be found at 20.00 m deep underground and will not be liquefied at seismic i...