某超限高层试桩设计与施工关键问题分析

Analysis of key issues in design and construction of test piles for an out-of-code high-rise building

以一实际工程的试桩设计与施工为背景,研究分析超限高层试桩设计与施工过程中的关键问题。该工程塔楼试桩共进行了三批(每批3根),第三批静载检测结果才满足设计要求,严重影响了工期。前两批试桩不满足设计要求的原因主要体现在两个方面,首先是混凝土强度不满足设计要求,其次是桩基施工工艺不能有效控制桩身质量和桩底沉渣厚度。通过三批试桩静载检测结果分析可以发现,超限高层塔楼的灌注桩承载力要求高,灌注桩施工应采取合理的施工工艺,试桩设计宜采取桩侧和桩端注浆工艺,才能尽快提高桩与周边土的摩擦力,使试桩尽快达到设计承载力。

Based on the design and construction of test piles in an actual project,the key issues in the design and construction of test piles for an out-of-code high-rise building were studied and analyzed.A total of three batches of piles were tested for the towers of this project(three in each batch),and the static load test results of the third batch met the design requirements,which seriously affected the construction period.The reasons for the failure of the first two batches of test piles to meet the design requirements were mainly reflected in two aspects.The first was that the concrete strength did not meet the design requirements,and the second was that the pile foundation construction technology could not effectively control the pile body quality and pile bottom sediment thickness.Through the analysis of the static load test results of three batches of test piles,it can be found that the load-bearing capacity of cast-in-place piles for out-of-code high-rise towers is high,and reasonable construction technology should be adopted for the construction of cast-in-place piles,and the design of the test pile should adopt the pile side and pile end grouting process to increase the friction between the pile and the surrounding soil as soon as possible,so that the test pile can reach the design bearing capacity as soon as possible.