柔性地基上高填方减载式涵洞受力特性
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摘要
高填方涵洞在我国西部山区高速公路中应用广泛,由于高填方荷载较大以及涵洞-填土之间的刚度差异引起的土压力集中,造成涵洞结构出现一系列病害。为了缓解涵顶应力集中,消除涵洞结构病害,改进了涵洞结构形式,即在一般盖板涵结构的侧墙正上方设置减载块,其与涵洞侧墙为一整体结构;减载块与涵洞顶板形成U型减载孔,在孔内铺设柔性填料,由此构成减载式涵洞结构。利用模型试验和数值模拟方法,分析了柔性地基条件下减载式涵洞的受力特性,结果表明数值模拟结果与模型试验结果一致。此外,讨论了刚性和柔性两种地基条件对减载式涵洞受力的影响规律。研究发现:涵洞在柔性地基条件下减载效果比刚性地基条件更好,涵洞结构受力更合理。实际工程中应该重视对柔性地基的处理,优先考虑满足工后沉降,不应刻意提高地基刚度。
High-fill culverts have been widely used in expressway in the western mountainous area of China. A series of damage occurs in culvert structure because of the large load of high fill and earth pressure concentration caused by the stiffness difference between the culvert and surrounding soil filled. In order to relieve the stress concentration and eliminate the structural damage, a new culvert structure is proposed, i.e., two load shedding blocks are set on both sidewalls of the general cover-plate culvert as an integral structure. The U-type load-shedding hole between two load-shedding blocks is filled with compressible material. The model test and numerical simulation were conducted to investigate the stress characteristics of the load-shedding culvert on the flexible foundation. The numerical simulation results are consistent with the measured results in model test. In addition, the influences of rigid and flexible foundation on stress states of load-shedding culvert are discussed. The load-shedding effect under the condition of flexible foundation is found better than that of rigid foundation, the stress states of the culvert are more reasonable. Hence, the ground treatment relevant to flexible foundation should be paid more attention in practical project, the requirement of post-construction settlement is more important than the foundation stiffness.
High-fill culverts have been widely used in expressway in the western mountainous area of China. A series of damage occurs in culvert structure because of the large load of high fill and earth pressure concentration caused by the stiffness difference between the culvert and surrounding soil filled. In order to relieve the stress concentration and eliminate the structural damage, a new culvert structure is proposed, i.e., two load shedding blocks are set on both sidewalls of the general cover-plate culvert as an integral structure. The U-type load-shedding hole between two load-shedding blocks is filled with compressible material. The model test and numerical simulation were conducted to investigate the stress characteristics of the load-shedding culvert on the flexible foundation. The numerical simulation results are consistent with the measured results in model test. In addition, the influences of rigid and flexible foundation on stress states of load-shedding culvert are discussed. The load-shedding effect under the condition of flexible foundation is found better than that of rigid foundation, the stress states of the culvert are more reasonable. Hence, the ground treatment relevant to flexible foundation should be paid more attention in practical project, the requirement of post-construction settlement is more important than the foundation stiffness.
引文
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[9]陈保国,宋丁豹,王云辉,等.减载式刚性涵洞减载机理与受力特性研究[J].华中科技大学学报(自然科学版),2016,44(4):79-84.CHEN Bao-guo,SONG Ding-bao,WANG Yun-hui,et al.Load reduction mechanism and stress characteristics of load-shedding culvert under high fill[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2016,44(4):79-84.
[10]CHEN BAOGUO,SONG DINGBAO,MAO XINYING,et al.Model test and numerical simulation on rigid load shedding culvert backfilled with sand[J].Computers and Geotechnics,2016,79:31-40.
[2]马强,郑俊杰,张军,等.高填方涵洞减载机制与数值分析[J].岩土力学,2010,31(增刊1):424-429.MA Qiang,ZHENG Jun-jie,ZHANG Jun,et al.Mechanism analysis and numerical simulation on load reduction for culvert beneath high filling[J].Rock and Soil Mechanics,2010,31(Supp.1):424-429.
[3]马强,肖衡林,李丽华.高填方涵洞加筋减载的数值模拟[J].长江科学院院报,2017,34(2):35-40.MA Qiang,XIAO Heng-lin,LI Li-hua.Numerical simulation on load reduction by reinforcement bridge of culvert beneath high filling[J].Journal of Yangtze River Scientific Research Institute,2017,34(2):35-40.
[4]张卫兵,刘保健,谢永利.基于EPS减荷措施的高填涵洞试验研究[J].公路交通科技,2006,23(12):54-57.ZHANG Wei-bing,LIU Bao-jian,XIE Yong-li.Field test and numerical simulation study on the load-shedding effect of EPS on the highly filled culvert[J].Journal of Highway and Transportation Research and Development,2006,23(12):54-57.
[5]SUN L,HOPKINS T,BECKHAM T.Stress reduction by ultra-lightweight geofoam for high fill culvert:numerical analysis[C]//Proceedings of the 13th Great Lakes Geotechnical and Geoenvironmental Conference.Milwaukee:[s.n.],2005:146-154.
[6]KANG J,PARKER F,YOO C H.Soil-structure interaction and imperfect trench installations for deeply buried concrete pipes[J].Journal of Geotechnical and Geoenvirnmental Engineering,2007,133(3):277-285.
[7]VASLESTAD J,JOHANSEN T H,HOLM W.Load reduction on rigid culverts beneath high fills:long-term behavior[J].Transport Research Record,1993(1415):58-68.
[8]陈保国,宋丁豹,焦俊杰,等.减载条件下高填方涵洞垂直土压力研究[J].华中科技大学学报(自然科学版),2015,43(10):112-116.CHEN Bao-guo,SONG Ding-bao,JIAO Jun-jie,et al.Vertical earth pressure on high fill culvert under load reduction condition[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2015,43(10):112-116.
[9]陈保国,宋丁豹,王云辉,等.减载式刚性涵洞减载机理与受力特性研究[J].华中科技大学学报(自然科学版),2016,44(4):79-84.CHEN Bao-guo,SONG Ding-bao,WANG Yun-hui,et al.Load reduction mechanism and stress characteristics of load-shedding culvert under high fill[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2016,44(4):79-84.
[10]CHEN BAOGUO,SONG DINGBAO,MAO XINYING,et al.Model test and numerical simulation on rigid load shedding culvert backfilled with sand[J].Computers and Geotechnics,2016,79:31-40.
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