基于碾压混凝土破坏特征研究  

Research on thefailure characteristics of roller compacted concrete

作　　者：张立军 谢超[2] ZHANG Lijun;XIE Chao(Gansu Yian Construction Technology Group Co.,Ltd.,Lanzhou 730060,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]甘肃一安建设科技集团有限公司,甘肃兰州730060 [2]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《混凝土》2024年第5期52-56,共5页Concrete

基　　金：长江学者和创新团队发展计划(IRT1139)。

摘　　要：以目前碾压混凝土重力坝坝体破坏特点为背景,利用扩张有限元数值方法,对碾压层厚度对大坝应力分布规律和裂缝扩展的影响进行了研究,并将在同一超载系数下的计算结果进行了比较,其中,超载系数从1.04~3.04,一共9种。在同样的过载条件下,裂缝的垂直延伸长度随碾压层的加厚而略有下降,裂缝的垂直延伸长度比正常情况下要小,仅在K=2.29、K=2.79两个位置与正常情况相当。大坝的压应力和物质的抗压强度相近,表明大坝在这个时候会出现总体失稳,而且裂缝的发展会转向沿河流的流向;在坝体各部位的材料达到对应的强度后,裂缝的横向发展速率会迅速增加,直至整个坝体的断裂。通过对4种不同荷载作用下坝体裂缝扩展深度、坝顶位移、坝踵及坝址处的受力情况进行了比较,结果显示,不同荷载作用下坝体裂缝呈现出脆性突发性破坏特征;结果表明:在荷载作用下,坝体裂缝扩展深度和坝顶位移均有一定程度的降低。In view of the failure characteristics of the current roller compacted concrete(RCC)gravity dam body,it uses the extended finite element numerical method to analyze the influence of the thickness of the roller compacted layer on the stress distribution and crack growth of the dam,and compares the calculation results when the overload coefficient is the same.There are nine overload coefficients from 1.04 to 3.04.The propagation law under the same overload coefficient indicates that the vertical propagation depth of cracks decreases slightly with the increase of the thickness of the compacted layer,and the vertical propagation depth is basically lower than that of normal concrete dams.Only when K-2.29 and K-2.79 are close to normal concrete dams.The compressive stress at the dam toe is close to the compressive strength of the material,indicating that the overall failure of the dam body will occur at this time,and the crack propagation direction will shift to the downstream direction;When the materials in each area of the dam approach their corresponding strength,the horizontal crack propagation speed will sharply increase,ultimately leading to the overall failure of the dam.The analysis of four models shows that the overall crack propagation depth,dam crest displacement,stress distribution patterns at the dam heel and toe are basically similar under each overload coefficient,and the dam cracks have the characteristics of brittle and sudden failure.Under the same overload coefficient,there is a small decrease in crack propagation depth and dam top displacement with the increase of the thickness of the compacted layer.

关 键 词：破坏特征 碾压混凝土 坝体 有限元 裂纹扩展 

分 类 号：TU528.01[建筑科学—建筑技术科学]