微型注浆桩复合地基处理沉降计算对比及规律分析

Settlement Analysis of Ground Improved by Micro Grouted Piles

微型注浆桩复合地基处理技术作为一项兼具排水加固、注浆加固、加筋增强作用的地基处理新工艺,常应用于上海、常熟等软土地区。由于其加固因素相互影响、作用机理复杂,目前尚未见相应的沉降计算方法。基于常熟耀皮汽车玻璃厂试验项目,通过复合地基变形计算方法、减沉复合疏桩沉降计算方法和桩网复合地基沉降计算方法,分析上部结构荷载作用下的地基总沉降,并采用天然地基扩散模型计算降水引起的总沉降,结合太沙基固结理论计算降水预固结沉降,提出了微型注浆桩复合地基沉降计算方法。在此基础上,结合典型地层条件分析降深、降水持续时间、使用荷载及降深荷载比等因素对沉降规律的影响。

As a new foundation improvement method,the micro grouted piles can achieve the consolidation,grouting and rein-forcement improvement of soft soils.It has been widely applied in soft soil areas such as Shanghai and Changshu.Due to the re-inforcement factors interact with each other,and the mechanism of pile-soil interaction is complex,the settlement estimation method has not been reported.Based on a trial project of the Changshu Yaopi project,the deformation estimation method of the composite ground,composite foundation with settlement reduction piles and the pile-net composite foundation are used to ana-lyze the total settlement under the upper structure loads.The unimproved natural foundation loading spreading model is used to estimate the total settlement caused by the dewatering effect.The surcharging settlement of the dewatering is estimated based on the Terzaghi consolidation theory.Then the settlement estimation method of the micro grouted pile composite foundation is proposed.On this basis,combined with the typical soil layer conditions,the influence of factors,such as dewatering depth,duration,service load and ratio of the dewatering depth to the service load,on the settlement are analyzed.