| 摘要: |
| 水闸普遍存在着可见和不可见的裂缝，带裂缝工作是水闸的常态，当受到寒潮的影响时，已有的细微裂缝会连通、扩展，甚至贯穿整个闸墩，严重影响结构的安全性和耐久性。扩展有限元法（XFEM）通过富集非连续位移模式，使得非连续位移场的表征独立于单元边界，可有效描述混凝土中的裂纹扩展。基于XFEM并结合热力耦合，研究了水闸在不同初始温度下，遭遇不同降温幅度及历时的寒潮作用时的渐进开裂破坏过程，并与某实际工程的开裂情况进行对比，数值模拟结果与现场情况基本吻合。研究结果表明，水闸遭遇寒潮时，靠近闸墩表面的温度与外界温度变化基本一致，靠近闸墩中心的温度变化较小，闸墩内外温差随着寒潮强度的增强而增大；闸墩混凝土的内表温差和约束是导致闸墩开裂的根本原因；裂缝分布在上下游墩头与底板相交的位置，随着寒潮强度的增强，裂缝与底板的夹角、长度及深度也随之增大，对水闸结构的不利影响也越大。因此，寒潮来临时应做好安全监测及混凝土防护工作，控制闸墩的温降以防止裂缝的开展。 |
| 关键词: 水闸 混凝土开裂 寒潮 扩展有限元法（XFEM） 温降 耐久性 |
| DOI： |
| 分类号:TV313 |
| 基金项目:国家创新研究群体科学基金资助项目（51321065）；水利工程仿真与安全国家重点实验室开放基金资助项目 |
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| Cracking behaviour analysis of sluices under the action of cold waves based on XFEM |
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LV Yang, ZHANG She rong, YU Mao, LI Hong-bi
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State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin
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| Abstract: |
| Both visible and invisible cracks are common in the sluices. As a result, it is normal for a sluice with cracks under operatin conditions. When affected by the cold waves, the microscopic cracks in the sluice that already exist would connect, extend, and even run through the sluices, which would seriously affect the safety and durability of the sluices. An extended finite element method （XFEM）can make the characterization of discontinuous displacement field independent of the cell boundaries by enriching discontinuous displacement mode on the influence domain of the related nodes. Based on the extended finite element (XFEM) and a heat-mechanical coupling method, the authors of this article have made studies of sluice’s gradual cracking failure process under different initial temperatures, different temperature drop ranges and durations of the cold waves. Compared with the actual cracking situation in a practical work, that the numerical computation agrees well with the real cracking situation. The analysis results indicate that when the sluice is affected by the cold waves, the temperature near its surface is approximate with the change of environment temperature; on the contrary, in the center section of the sluice there is no great changes in temperature. The gate pier’s inside and outside temperature difference increases with the increases in the cold waves. The basic reason of cracking in the sluices is the combination of the inside temperature differences with their constraints. The cracks appear at the place where the gate pier links the floor, and with the augmentation of the cold waves, the angle, the length and the depth between the crack and the bottom also increase, which would be much more unfavorable to the gate pier. Therefore, it is necessary to make a good job of safety monitoring and protection for the gate pier to control cracks in the piers caused by temperature drop before the cold waves’ coming. |
| Key words: sluice concrete cracking cold waves an extended finite element method (XFEM) drop in temperature concrete durability |
