1. 长安大学 公路学院,陕西,西安,710064
2. 广东省高速公路有限公司,广东,广州,510623
网络首发:2023-01-13,
纸质出版:2023
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冯忠居, 王思琦, 王溪清, 等. 沟谷地形对高填方拱涵涵周土压力影响研究[J]. 岩土力学, 2023,44(1):119-130.
FENG Zhong-ju, WANG Si-qi, WANG Xi-qing, et al. Influence of valley topography on earth pressure of high-fill arch culvert[J]. 2023, 44(1): 119-130.
冯忠居, 王思琦, 王溪清, 等. 沟谷地形对高填方拱涵涵周土压力影响研究[J]. 岩土力学, 2023,44(1):119-130. DOI: 10.16285/j.rsm.2022.0297.
FENG Zhong-ju, WANG Si-qi, WANG Xi-qing, et al. Influence of valley topography on earth pressure of high-fill arch culvert[J]. 2023, 44(1): 119-130. DOI: 10.16285/j.rsm.2022.0297.
沟谷地形下高填方涵洞土压力分布规律较为复杂,不同沟谷地形下涵周土压力分布规律与上埋式涵洞差异显著。为探明沟谷地形对高填方拱涵涵周土压力的影响,采用离心模型试验与数值模拟方法,建立了地形−涵洞−填土的相互作用模型,分析了不同沟谷宽度B、沟谷坡度 a 下的拱涵涵周土压力及涵顶土压集中系数Ks的分布规律,并与最新涵洞设计规范进行了对比,阐述了沟谷地形下高填方拱涵土压力形成机制。研究表明:(1)沟谷宽度B对涵顶土压力集中系数Ks影响显著,沟谷宽度B为4D~6D,D为拱涵的净跨径,涵顶土压力集中系数Ks增幅较大;(2)沟谷宽度B小于4D时,可发挥沟谷地形对涵洞的减载作用;(3)沟谷坡度a 在45°~60°时,涵顶土压力及其Ks变化最显著;(4)填土高度为20 m,a >70°时,Ks ≤1。填土高度为40 m,a >50°时,Ks ≤1;(5)我国最新涵洞设计规范推荐的Ks与离心模型试验、数值模拟规律存在一定差异,当a =45°时,沟谷宽度 B 较小时,规范的涵顶土压力集中系数 Ks 较为保守;(6)沟谷地形下高填方拱涵 Ks 与拱顶压密区、等压面的形成有关。拱顶压密区可引起拱涵涵顶土压力集中,并引起压密区周边土体的竖向土压力呈拱形分布。在接近地表一定深度处,拱形分布逐渐向水平分布过渡,从而形成等压面。等压面上部荷载将分散于沟谷坡体,故可发挥沟谷地形的卸荷效应。
High-fillculverts placed in valley topography have a complex earth pressure distributionlaw due to their locations around culverts in various valley topographyconditions. In order to investigate the influence of valley topography on theearth pressure around the culvert of high-fill arch culverts
a interactionmodel of "topography-culvert-fill" was established by usingcentrifugal model test and numerical simulation method. Additionally
thedistribution laws of earth pressure around the arch culverts and earth pressureconcentration coefficient at the top of the culvert underdifferent valley widths and valley slopes were analyzed and were compared with the latest Chinese culvert design code.Furthermore
the mechanism of earth pressure formation of high-fill archculverts under valley topography was presented. The research findings are as follows:(1) The influence of the valley width on the earth pressureconcentration coefficient at the top of the culvert issignificant
and the increment of the earth pressure concentration coefficient at the top of the culvert is larger when is 4−6(isthe clear span of arch culvert). (2) When is lessthan 4
the topography would play the role of load reduction to theculvert. (3) With valley slopes ranging from 45° to 60°
the earth pressure atthe tops and would be affected dramatically. (4) When fillheight is 20 m with >70°
≤1; and when 40 m fill height with >50°
≤1. (5) The recommended by the latest Chineseculvert design code differs to some extent from those by centrifugal model testand numerical simulation. In the case of =45° with a small value
the earth pressure concentration coefficient at thetop of a culvert of the code is more conservative. (6) ofhigh-fill arch culvert in valley is related to the formation of arch topcompaction area and isobaric surface. The arch top compaction area can causethe earth pressure concentration on the top of the arch culvert
and cause thevertical earth pressure of the soil around the compaction area to be arched. Ata certain depth approaching the surface of the fill
the arch distributiongradually transits to the horizontal distribution
thus forming an isobaricsurface. The upper load of the isobaric surface will be dispersed on the valleyslope
so the unloading effect of the valley topography can be exerted.
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