农业工程学报2018，Vol.34Issue(12)：162-170,9.DOI:10.11975/j.issn.1002-6819.2018.12.019
北方寒冷地区水渠的地震动力响应特征
Seismic response characteristics of canal in northern cold regions
摘要
Abstract
Because of its direct influence on the amount of unfrozen water and ice lens in a frozen soil, temperature has a significant effect on the mechanical behavior of the freeze-thaw soil. Accordingly, seismic responses of engineering structures such as canals in northern cold regions exhibit noticeable differences with seasonal alternation. To analyze the distinctive seismic characteristics of a canal in northern cold regions, a coupled water-heat-dynamics model was built based on theories of heat transfer, soil moisture dynamics, frozen soil mechanics, and soil dynamics. A well-monitored canal in northern cold regions was used to simulate seismic responses in two typical seasons in the 10th service year. The numerical results showed that the constructed canal disturbed the original thermal state and the geo-temperatures of the canal changed with seasonal alternation. In the freezing-thawing process, the unfrozen water migrated and ice lens formed in the canal soil under the forcing of temperature gradient. As a result, the unfrozen water and ice distributions of the canal exhibited obvious seasonal differences. For instance, there were little unfrozen water and much ice lens in the canal and shallow layer of soil at air temperature bellowing freezing, whereas the volumetric content of the unfrozen water was high and the ice content was equal to 0 when the temperature had its maximum during the year ( July 15). So the differential seismic responses of the canal were generated by different water-heat states in the two seasons. Among these two seasons in the 10th service year, although the general time histories of the acceleration and velocity were similar in the canal, their maximum amplitudes were relatively larger on July 15. For instance, in two different time (January 15, July 15), the accelerations of the canal bottom respectively got their maximum acceleration values which were 1.160, 1.360 m/s2in 12.165 and 2.404 s, whereas the accelerations of the canal top got their respectively in 8.995 s and 9.007 s maximum values which were 1.476, 1.785 m/s2, so the earthquake accelerations of the canal were stronger on July 15 than January 15 under the earthquake. The horizontal velocity responses of the bottom and the top of the canal were smaller on January 15, their maximum velocity was 0.145 and 0.149 m/s, respectively, while the maximum speed was 0.146 m/s and 0.150 m/s, respectively on July 15. The displacement was a direct expression of the seismic loading and also sensitive to temperature variation, the displacement responses of the canal to dynamic loading are also relatively larger on July 15 and the maximum horizontal displacement was 5.6 cm in the example. When the earthquake was over, there were still permanent differential deformations in the canal, and the residual displacement distributions of the canal were asymmetrical. In fact, the seismic response of the canal in seasonally frozen soil area was a very complicated water-heat-dynamic coupled problem, so there were few theoretical documents on the subject up to now. As a preliminary study, the numerical model proposed in this paper has some limitations. Therefore, further studies should be carried out on the subject. As a preliminary exploration, it is expected to provide theoretical basis and reference for design, construction, and maintenance of the canal in seasonally frozen regions.关键词
渠道/冻土/温度/寒冷地区/地震响应/数值模型/季节Key words
canal/frozen soil/temperature/cold regions/seismic response/numerical model/season分类
建筑与水利引用本文复制引用
欧尔峰,李双洋,刘德仁..北方寒冷地区水渠的地震动力响应特征[J].农业工程学报,2018,34(12):162-170,9.基金项目
国家自然科学基金资助项目(41672315 （）
41230630) （）
中国科学院前沿科学重点研究项目(QYZDY-SSW-DQC015) （QYZDY-SSW-DQC015）
中国科学院"西部之光"项目(李双洋) （李双洋）
中国科学院青年创新促进会 （）
冻土工程国家重点实验室自主研究课题(SKLFSE-ZY-18) （SKLFSE-ZY-18）
中国科学院STS项目(HHS-TSS-STS-1502) （HHS-TSS-STS-1502）
