水下浇注混凝土膜效应机理

随着现代地连墙工程的广泛应用，水下浇注混凝土埋管深度控制不精确和基坑开挖后地连墙大面积露筋问题逐渐暴露出来。为了加强地连墙施工过程质量控制、提高地连墙墙体质量，以水下浇注混凝土为考察对象，首次提出水下浇注混凝土膜效应及其形成阶段和性质的概念，同时提出膜效应以膜厚度作为衡量标准和以膜阻力作为表征方法的理念，根据现场试验和理论分析得出膜效应的影响因素，并提出控制埋管深度的主要措施。根据膜效应和地连墙大面积露筋的特点，首次提出水下浇注混凝土边膜滞留效应的概念和影响因素，对地连墙大面积露筋事故的成因进行分析，并提出减少地连墙大面积露筋的主要措施。

Mechanism of membrane effect during pouring of underwater concrete

With the broad application of modern diaphragm wall engineering,problems including inaccurate depth of buried pipes control during pouring of underwater concrete and large-area exposure of the reinforced bar for the diaphragm wall after excavation of the foundation pit exposed gradually.For the purposes of strengthening the project process control and improving the quality of diaphragm wall,we put forward the concept of the membrane effect of underwater pouring concrete and its formation stages and nature for the first time taking the underwater pouring concrete as the investigation objective.At the same time we put forward the concept of taking the membrane thickness as the measurement standard and the membrane resistance as the characterization method.According to field tests and theoretical analyses,we get to know the influential factors of the membrane effect,and put forward main measures for controlling the depth of buried pipes.According to the characteristics of the membrane effect and large-area exposure of the reinforcement,we put forward the concept of edge-membrane stranding effect and the influential factors for the first time.Based on the cause analysis of large-area reinforcement exposure,we put forward main measures for reducing the large-area reinforcement exposure.