淤泥质软土地层中扩大头锚索的极限抗拔承载力研究  

Study on the ultimate uplift bearing capacity of expanded anchor cable in muddy soft soils layer

作　　者：马龙祥[1] 余云翔 杜文 李毅[1] 杨浩[1] 李弘毅 Ma Longxiang;Yu Yunxiang;Du Wen;Li Yi;Yang Hao;Li Hongyi(The Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education,Chengdu 610031,China;Shenzhen Engineering Company of CREGC,Shenzhen 518034,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [2]深圳中铁二局工程有限公司,广东深圳518054

出　　处：《建筑科学》2023年第3期81-91,共11页Building Science

摘　　要：为探明软土地层中扩大头锚索极限抗拔承载力的主要影响因素及量值特征,首先应用数值模拟的方法对软土地层中扩大头锚索承受拉拔力作用时周围地层的响应规律以及影响极限抗拔力的主要因素进行分析,而后充分考虑杆体倾角对极限抗拔力的影响,进一步推导适用于软土地层中扩大头锚索极限抗拔承载力的理论计算公式。研究结果表明:①软土地层中扩大头锚索的拉拔力对锚索体周围土体的影响仅局限在锚固段附近的一个很小范围内;②随着拉拔力的不断增大,土体塑性区会率先出现在锚固段侧壁靠近承载体附近区域,而后逐渐沿侧壁向锚固段中部扩展,直至最终贯通整个扩大头锚固段并延伸至锚固段前后一定范围土体;③扩孔直径、锚固段长度、地层摩擦角以及杆体倾角对扩大头锚索的极限抗拔力影响均较大,但相较而言,增大扩孔直径对提高扩大头锚索的极限抗拔承载力更为有效;④提出的理论计算公式可以对淤泥质软土地层中扩大头锚索的极限抗拔承载力进行较为可靠的分析。To ascertain the main influencing factors and quantitative characteristics of the ultimate uplift bearing capacity of the expanded anchor cable in the soft soil layer,the numerical simulation method is used to analyze the response law of the surrounding strata and the main factors affecting the ultimate uplift bearing capacity of the expanded anchor cable in the soft soil layer.Then,the influence of the inclination angle of the rod on the ultimate uplift bearing capacity is fully considered,and the theoretical calculation formula suitable for the ultimate uplift bearing capacity of the expanded anchor cable in the soft soil layer is further deduced.The results show that:①The influence of the pullout force of expanded anchor cable on the soil around the anchor cable body is limited to a small range near the anchorage section in soft soil.②With the increase of pull-out force,the plastic zone of soil will first appear near the sidewall of the anchorage section near the bearing carrier,and then gradually expand along the sidewall to the middle of the anchorage section until the whole enlarged head anchorage section is finally penetrated and extended to a certain range of soil before and after the anchorage section.③The diameter of the expansion hole,the length of the anchorage section,the friction angle of the stratum,and the inclination angle of the rod have a great influence on the ultimate uplift force of the expanded anchor cable.However,the increase of the diameter of the expansion hole is more effective to improve the ultimate uplift bearing capacity of the expanded anchor cable.④The proposed theoretical calculation formula can reliably analyze the ultimate uplift bearing capacity of expanded anchor cable in muddy soft soils layer.

关 键 词：淤泥质软土 扩大头锚索 极限抗拔力 影响因素 计算公式 

分 类 号：TU43[建筑科学—岩土工程]