钢护筒嵌岩桩基联合受力响应特性试验研究

陈贵发 朱峰

摘要：为了掌握钢护筒桩基础的受力特性与破坏机理，提高工程结构的安全性，以某内河直立码头项目为研究对象，开展了1∶20的室内钢护筒嵌岩桩模型试验，分别对普通预制桩和钢护筒预制桩进行了嵌岩竖向承载试验和水平承载试验，对比分析了有钢护筒和没有钢护筒的条件下，桩体嵌岩深度对桩基承载性能的影响。分析结果表明，由于钢-岩土界面的咬合力较弱，钢护筒嵌岩桩的竖向承载力略小于普通嵌岩桩的竖向承载力;钢护筒对桩身刚度的加强可以将桩顶水平荷载的作用效应放大传递至钢护筒下端面，导致下端面的混凝土呈水平向脆性剪切破坏，从而可能降低钢护筒嵌岩桩的水平承载力。研究结果可以为钢护筒嵌岩桩码头结构设计提供数据参考。

关键词：港口工程;嵌岩桩;钢护筒;模型试验;承载力

中图分类号：TU45文献标识码：ADOI： 10.7535/hbgykj.2021yx03013

Abstract：In order to master the stress characteristics and failure mechanism of steel casing pile foundation and improve the safety of engineering structure， the 1∶20 indoor model test of rock embedded steel casing pile was carried out by taking an inland river vertical wharf as the research project. The vertical bearing test and horizontal bearing test of common precast piles and steel casing precast piles were carried out respectively， and the influence of rock embedded depth on the bearing capacity of pile foundation with and without steel casing. The results show that the vertical bearing capacity of the steel casing rock embedded piles is slightly less than that of the ordinary rock embedded piles due to the weak bite force of the steel-soil interface; the reinforcement of pile stiffness by steel casing can amplify the effect of horizontal load on pile top and transfer it to the lower end face of steel casing， resulting in horizontal brittle shear failure of concrete at the lower end face， which may reduce the horizontal bearing capacity of rock embedded piles with steel casing. The research results can provide data reference for the structural design of steel casing rock embedded pile wharf.

Keywords：port engineering; rock embedded pile; steel casing; model test; bearing capacity

近年來，得益于内地大型水利设施的不断完善，各大干线航道的通航水深条件均得到巨大改善[1-2]。长江航道沿途新增设了多个深水港口，内河航运的优势得到了进一步充分发挥[3-4]。框架式直立码头作为一种可以通过分层系缆而适应水位变化的水工结构形式，在内河港口建设中得到了广泛应用[5-6]。

受到施工工艺的影响，内河码头施工过程中通常需要在泥质岸坡中提前埋入钢护筒直到基岩作为钢筋混凝土桩基的成桩支护，然而在成桩完成后，钢护筒一般直接保留于原地，从而形成钢护筒嵌岩桩复合基础[7]。……