大坝混凝土界面力学性能的测试与数值模拟研究

提出了一种测试大坝全级配混凝土界面力学性能的试验分析方法，通过钻芯、切割、研磨、制备含界面小试件(15 mm x 30 mm x 120 mm长方体)，采用高精度位移传感器(分辫率0. O 1 N,m ) , 微变形夹具和数据处理系统，对配合比优化前后的三峡大坝混凝土的界面强度进行了测试研究，涉及的大骨料区域应力应变的量化成果鲜有文献报道。测试结果发现，混凝土界面强度测值虽有离散，但大体分布在一定范围内，规律上配合比优化后0. 5水胶比的混凝土平均界面强度大于配合比优化前 0. 6水胶比的混凝土近30%，且更接近砂浆强度本体，接近度高约10%。根据对混凝土细观数值模拟研究表明，以实测界面强度为参数，通过损伤和尺寸系数修正，计算得到的混凝土宏观轴拉强度与试验测值相近，且随细观界面强度提高而增长。本文的研究结果进一步表明通过优化配合比改善混凝土细观界面强度，使得界面强度更加接近砂浆本体的强度，可提高混凝土的宏观力学性能。

Testing and numerical simulation on mechanical properties of dam concrete interface

A method for testing and analyzing the mechanical properties of dam concrete interface is put forward herein,with which the concrete interface strength of the Three Gorges Dam before and after the optimization of the concrete mixing ratio is tested and studied with high precision displacement sensor and the micro-deformation fixture as well as the data processing systems through the process of coring,cutting,grinding,preparation of the small specimens containing interfaces.The testing results show that though the measured values of the interface strength of concrete are a little dispersed,they are generally distributed within a certain range.Generally,the average interface strength of the concrete with the optimized water-cement ratio of 0.5 is nearly 30% higher than that of the concrete with the water-cement ratio of 0.6 before the optimization concerned,and then is more close to the mortar strength with the approach degree higher by about 10%.The study with the meso-scopic numerical simulation on the concrete shows that the calculated macro-tensile strength of the concrete is close to that of the measured one and increased along with the strength enhancement of the meso-scopic interface through the corrections made on damages and size factors by taking the measured interface strengths as the parameters concerned.The result of this study further indicates that improving the meso-scopic interface strength with the optimization of the mixing ratio to make the interface strength more close to the mortar strength can surely enhance the macro-mechanical properties of concrete.