填料蠕变性能对高填方明洞减载效果的时效性分析  

The influence analysis of the creep properties of backfill soil on the load reduction effect of high-filled cut-and-cover tunn

作　　者：王昱杰 李盛[1] 贾聂宇驰 马莉[1] 王长丹[2] WANG Yujie;LI Sheng;JIANIE Yuchi;MA Li;WANG Changdan(Civil Engineering College,Lanzhou Jiaotong University,730070 Lanzhou,China;Key Laboratory of Road&Traffic Engineering,Ministry of Education,Tongji University,201804 Shanghai,China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070 [2]同济大学道路与交通工程教育部重点实验室,上海201804

出　　处：《应用力学学报》2025年第1期71-80,共10页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金资助项目(No.51668036,51868041);甘肃省基础研究创新群体资助项目(No.21JR7RA347);甘肃省科技计划资助(No.21YF5GA050);甘肃省教育厅产业支撑计划资助项目(No.2021CYZC-28)。

摘　　要：为明确高填方明洞采用相对低压实黄土(relatively low-compacted loess,RLC)减载时,回填材料蠕变性能对明洞上方土压力的影响。利用有限差分软件FLAC3D,分析了填料蠕变性能显著(黄土)和不显著(砂砾石)时,RLC减载层所发挥的减载作用,同时进一步研究了RLC减载层宽度、高度和位置的变化对高填方明洞上方的竖向土压力的长期影响。研究结果表明,填料的蠕变性能对RLC减载层减载效果的时效性影响显著,在蠕变性能不显著的填料中,RLC减载层可以发挥更好的减载效果。填料回填完成时,RLC减载层通过增加明洞顶部的填料相对竖向位移来有效减小明洞顶的竖向土压力。工后,若填料为黄土,RLC减载层及填料的沉降均随时间不断增加,洞顶土压力会随时间增大,RLC减载效果随时间减弱;若填料为砂砾石,仅RLC减载层的变形会随时间增加,洞顶土压力随时间减小,RLC减载能力随时间增大。另外,RLC减载层的几何参数变化对高填方明洞上方土压力的长期影响与填料的蠕变性能密切相关,且存在最优值。以上结果对高填方明洞的长期减载有一定的参考价值。We aimed to study the influences of creeping properties of different backfill materials on the earth pressure above the high-filled cut-and-cover tunnel(HFCCT)that adopted the relatively low-compacted loess(RLC)as the load reduction method.The FLAC3D(fast lagrangian analysis of continua)was used to establish numerical models of HFCCT to analyze the RLC reduction effects when the creep properties of the backfill materials were significant(loess)and insignificant(dry sandy gravel)respectively.At the same time,the influences of the related parameters variations(the width of RLC,the height of RLC and the location of RLC)on the vertical earth pressure above the HFCCT were further investigated.The results show that the load reduction effect of RLC is different under different backfill materials.The RLC load reduction can exert a better load reduction effect in fillers with insignificant creep properties.When backfill works are completed,the load reduction effect of RLC is activated by generating the relative vertical displacement difference between the backfill materials above the HFCCT and the both sides of HFCCT.After construction,if the backfill material is loess with significant creeping property,the displacement of the RLC and backfill material increases over time,the vertical earth pressure above HFCCT also increases over time,which indicates the load reduction effect of RLC gradually decreases.If the creep property of backfill material is insignificant,the displacement of RLC still increases over time,but the vertical earth pressure above HFCCT decreases over time,which suggests the load reduction effect increases.In addition,the long-term effect of changes in the geometric parameters of the RLC on the earth pressure above the HFCCT is closely related to the creeping properties of the backfill materials,which has an optimal value.The above results have certain reference value for the long-term load reduction of HFCCT.

关 键 词：高填方 相对低压实黄土 减载效应 数值模拟 蠕变 黄土 砂砾石 

分 类 号：TU43[建筑科学—岩土工程]