岩土力学 ›› 2018, Vol. 39 ›› Issue (12): 4597-4604.doi: 10.16285/j.rsm.2017.0975

• 岩土工程研究 • 上一篇    下一篇

强风化岩中挖孔基础抗拔试验及荷载位移曲线 模型参数研究

崔 强1,程永锋1,鲁先龙1,谢 枫2,孙付涛2   

  1. 1. 中国电力科学研究院有限公司,北京 102401;2. 中国能源建设集团安徽省电力设计院有限公司,安徽 合肥 230088
  • 收稿日期:2017-05-15 出版日期:2018-12-11 发布日期:2019-01-01
  • 作者简介:崔强,男,1980年生,博士,正高级工程师,主要从事输电线路杆塔基础方面的科研和试验检测工作。
  • 基金资助:
    国家电网公司科技项目(No. GCB17201600230)。

In-situ pull-out test and parametric study of load-displacement model for hole digging foundation in the strong weathered rock mass

CUI Qiang1, CHENG Yong-feng1, LU Xian-long1, XIE Feng2, SUN Fu-tao2   

  1. 1. China Electric Power Research Institute, Beijing 102401, China; 2. China Energy Construction Group Anhui Electric Power Design Institute Co., Ltd., Hefei, Anhui 230088, China
  • Received:2017-05-15 Online:2018-12-11 Published:2019-01-01
  • Supported by:
    This work was supported by the State Grid Corporation Science and Technology Project (GCB17201600230).

摘要: 挖孔基础是目前我国山区架空输电线路强风化岩地基中最常用的基础形式之一。以强风化岩地基中的直柱型、扩底型两种结构型式的挖孔基础为研究对象,通过开展16个全尺寸基础现场抗拔试验,获得各试验基础和地表不同位置处的荷载-位移曲线。试验结果表明:基础及地表的荷载-位移曲线整体变化特征相似,均可划分为初始直线段、中间曲线段和终了直线段3个特征段。采用M值表示相应阶段位移量占总位移的百分比,不同的特征段M值的大小不同,并且其值随着远离基础边缘而逐渐减小。分别对直柱型、扩底型两种结构型式的基础荷载-位移曲线进行归一化处理,采用双曲线模型获得无量纲荷载(Q/QL2)与上拔位移s之间的关系曲线,通过对比分析同种结构型式挖孔基础在黄土、强风化岩两种地基中荷载-位移曲线的差异性,得出地基岩土体抗剪强度参数c、? 值与双曲线模型参数b值呈负相关,与基础抗拔承载力呈正相关。采用推荐的模型及参数对挖孔基础的荷载位移曲线进行预测,预测值与试验值吻合较好,从而验证了该模型及参数对于强风化岩地基挖孔基础荷载-位移变化行为预测的适用性。

关键词: 强风化岩地基, 全尺寸挖孔基础, 现场上拔试验, 荷载-位移曲线, 上拔极限荷载, 双曲线模型参数

Abstract: The hole digging foundation in the strong weathered rock mass is often considered as the main footing form of overhead transmission line project in mountainous area. This paper focused on the shaft foundations and the spread foundations embedded in the strong weathered rock mass. The load-displacement relationships of sixteen full-size foundations were obtained through a series of full-scale pull-out test in site. The test results show that the load-displacement curves of the foundation are similar as that of on the ground surface. They can be divided into three stages: initial straight-line phase, transition curve phase and ending straight line phase. The parameter M is selected to represent the percentage of displacement in the corresponding stage. The M values at different load-displacement stages are different. M decreases as the distance away from the foundation edge increases. A normalized load-displacement curve obeying the hyperbolic relation for the shaft foundations and the spread foundations was presented, and parameters Q/QL2 and s were conducted by curve fitting. The comparative analysis for the same footing under different foundation conditions such as loess and strong weathered rock shows that the parameter b value is negatively related to the shear strength parameters of soil or rock. The uplift bearing capacity of foundation in above two foundation conditions increases successively with shear strength parameter c and ?. Finally, comparative analysis of the predict results using hyperbolic model proposed in the paper and the field test results concludes that the evaluation model to load-displacement response above was available in engineering design.

Key words: strong weathered rock, full-size digging hole foundation, pull-out test in site, load-displacement curve, ultimate uplift load, hyperbolic model parameters

中图分类号: 

  • TU 452
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