高面板堆石坝软接缝挤压特性试验研究

Compression test of soft joint in high concrete-faced rockfill dams

在高面板堆石坝工程中,在面板坝轴向受压区设置软接缝是防止面板发生挤压破损的常用工程措施之一。本文模拟软填缝料在面板纵缝中所受到的实际强约束条件,研制软接缝挤压特性试验装置,采用不同邵尔硬度和品种的橡胶开展挤压特性试验,分析填缝料在挤压过程各阶段的受力变形特点。试验结果表明,挤压特性曲线可分为初始调整段、平稳压缩段和强化挤压段三个阶段。在挤压过程中,由于强约束作用,填缝料的挤出效应是导致强化挤压段挤压模量快速增长的主要原因。橡胶的法向挤压特性不仅取决于邵尔硬度,不同的橡胶品种也有很大的影响。基于试验成果,提出一个可描述面板坝面板软接缝挤压特性的多项式挤压模型,拟合得到了挤压模型的模型参数。

The soft joints are widely applied in high concrete-faced rockfill dams.This type of joint is usually used to prevent the extrusion damage of the concrete face.To reproduce the actual loading and deformation conditions of soft joint,a test apparatus is developed.A series of laboratory tests are performed by using the rubber as the soft filler.The loading and deformation features of soft joint are analyzed for different loading status.The test results indicate that the deformation of soft joint can be divided into three stages:the initial stage,the steady stage,and the hardening stage.Due to the strong constrained condition,strong squeeze-out is observed during the hardening stage,giving rise to rapid increase of extrusion modulus.Based on the test results,a polynomial extrusion model is proposed.This model is applicable for the finite element simulation and the evaluation of soft joint.