摘要
为精确分析湖南省益娄高速公路桥梁基桩下伏溶洞顶板稳定性,基于有限差分软件FLAC3D建立了椭球形溶洞的三维数值分析模型,并设计了不同溶洞顶板跨度和厚度时的工况,采用强度折减法分析了溶洞顶板的稳定性、塑性区发展规律,结合二分法求得各工况下的顶板安全系数,研究结果表明:在基桩荷载下,溶洞两侧及基桩底部最先出现塑性区,随折减系数增大,塑性区贯通顶板产生拉剪破坏;顶板安全系数随顶板跨度增大而降低,随厚度增大而提高;以安全系数1.5作为桥梁基桩下伏溶洞顶板安全储备要求值,为工程实践中桥梁基桩的设计及溶洞顶板安全持力层的确定提供了参考。
In order to analyze the stability of Yi-Lou highway bridge pile＇s karst carve roof accurately in Hunan province,the FLAC^3D software was used to build the three dimensional numerical analysis model of ellipsoidal cave,the working conditions of the different karst cave roof span and thickness were designed. The stability of karst cave roof and the plastic zone development regularity were analyzed by using strength reduction method,combining with the dichotomy,the safety coefficient of cave roof was obtained. The results show that： Under the load of pile foundation,at the beginning,both sides of cave and the bottom of pile appeared plastic zone; with the increasing of reduction coefficient,the plastic zone connected,the roof made tension-shear failure; the roof safety factor decreases with the increasing of the span of karst cave and increases with the increasing of the thickness of roof; Use a safety factor of 1. 5 as the cave roof safety stock requirement value and provide theoretical guidance for the bridge pile foundation designing and determination of the stress layer.
出处
《公路工程》
北大核心
2016年第2期231-235,共5页
Highway Engineering
基金
湖南省交通运输厅科技进步与创新计划资助项目(201417)
关键词
桥梁基桩
溶洞
顶板稳定性
强度折减法
bridge pile
karst cave
the stability of karst cave roof
strength reduction method
