基于离散单元法的灰岩地区串珠溶洞承载力分析  

Bearing Capacity Analysis of Beaded Karst Cave in Limestone Area Based on Discrete Element Method

作　　者：周标 丁小彬 任续锋 Zhou Biao;Ding Xiaobin;Ren Xufeng(China Railway 16th Bureau Group Road and Bridge Engineering,Co.,Ltd.,Beijing 101500,China;School of Civil Engineering&Transportation,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]中铁十六局集团路桥工程有限公司,北京101500 [2]华南理工大学土木与交通学院,广州510641

出　　处：《科技通报》2023年第8期55-61,共7页Bulletin of Science and Technology

基　　金：国家自然科学基金项目(41827807);广东省现代土木工程技术重点实验室(2021B1212040003)。

摘　　要：研究桩基荷载作用下的溶洞稳定性对建筑工程有着重要的意义。本文以广州市白云机场北某项目为依托,利用PFC2D颗粒流软件,建立灰岩地层下桩基溶洞离散元模型,研究串珠溶洞的溶洞距离、串珠溶洞下方溶洞径长和桩基贯穿溶洞嵌岩深度3个不同影响因素对桩基承载力的影响。主要结论如下:(1)在桩基下伏双溶洞情况下,溶洞间距的增加会提高桩基极限承载力,当溶洞距离超过6倍桩径,增加溶洞间距对桩基承载力基本无影响;(2)在桩基下伏双溶洞情况下,下方溶洞径长的增大会降低桩基极限承载力,当下方溶洞径长超过6倍桩径时,增加下方溶洞径长对桩基承载力基本无影响;(3)对于桩基贯穿溶洞,当嵌岩深度大于桩体径长时,此桩基的极限承载力接近于无溶洞情况下的桩基承载力,提高嵌岩深度对桩基承载力几乎基本无影响。Studying the stability of karst cave under the load of pile foundation is of great significance to building engineering.Based on a project in the north of Baiyun Airport in Guangzhou City,this paper establishes the discrete element model of pile foundation karst cave under limestone stratum by using PFC2D particle flow software,and studies the influence of three different influencing factors,namely,the distance of beaded karst cave,the diameter length of karst cave under the bead cave and the rock embedding depth of pile foundation through the karst cave,on the bearing capacity of pile foundation.The main conclusions of this paper are as follows:(1)In the case of double karst caves under the pile foundation,the increase of the distance between karst caves will increase the ultimate bearing capacity of pile foundation,and when the distance of karst cave is more than 6 times the pile diameter,increasing the distance between karst caves has no effect on the bearing capacity of pile foundation.(2)In the case of double karst caves under the pile foundation,the increase of the diameter length of the lower karst cave will reduce the ultimate bearing capacity of the pile foundation,and when the diameter length of the lower karst cave is more than 6 times of the pile diameter,increasing the diameter length of the lower karst cave has no effect on the bearing capacity of the pile foundation.(3)For the pile foundation running through the karst cave,when the rock-socketed depth is greater than the pile diameter length,the ultimate bearing capacity of the pile foundation is close to that of the pile foundation without karst cave,and increasing the rock-socketed depth has almost no effect on the bearing capacity of the pile foundation.

关 键 词：离散元 数值模拟 桩基溶洞模型 稳定性分析 

分 类 号：TU473[建筑科学—结构工程]