混凝土桥梁防水粘结层剪应力的影响因素分析

The Influential Factor Analysis on Waterproof Tack Coat Shearing Strength of Concrete Bridge

通过建立混凝土桥梁桥面铺装的3D有限元模型,分析不同荷载水平、车辆行驶状态,以及防水粘结层厚度、模量和泊松比等不同影响因素对防水粘结层内部最大剪应力的影响.计算结果表明：荷载水平是防水粘结层剪应力的重要影响因素,超载率为140％时最大剪应力可达到标准轴载的1.63倍,行车状态对防水粘结层最大剪应力影响有限;经过沥青铺装层的应力扩散以后,车辆行驶状态的变化对防水粘结层最大剪应力影响有限;防水粘结层所受最大剪应力随厚度的变化很小,但对模量和泊松比变化较为敏感;较为坚硬的防水粘结层材料（模量在200～ 300MPa之间,泊松比在0.25～0.35）,对自身抗剪切疲劳较为有利.

By setting up the 3D finite element model covered on the concrete bridge floor, different load level and vehicle travel condition, as well as the influence of different factors, such as waterproof tack coat thickness, modulus and Poisson ratio, on maximum shearing stress inside the waterproof tack coat shall be analyzed. The calculating results showed that the load level is an important influencing factor on the shearing strength of waterproof tack coat ; the maximum shearing strength can reach 1.63 times of the standard axle load when the overloading rate is 140%, and the travelling condition has a limited effect on the maximum shearing stress of waterproof tack coat; after the stress dispersion of pitch pavement layer, variation of vehicle travelling condition has a limited effect on maximum shearing stress of waterproof tack coat; the maximum shearing stress of waterproof tack coat shall be reduced along with the thickness variation, but it is sensitive to the variation of modulus and Poisson ratio ; the hard waterproof tack coat material （200 -300MPa modulus and 0.25 -0.35 Poisson ratio） is relevantly beneficial to its anti - sheafing fatigue.