季节性冻土区能量桩位移变化规律
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作者:
作者单位:

1.重庆大学 土木工程学院;2.山地城镇建设与新技术教育部重点实验室,重庆 400045

作者简介:

彭宸(1998- ),男,主要从事能量桩—土相互作用研究,E-mail: cqupcc@163.com。
PENG Chen (1998- ), main research interest: energy pile-soil interaction, E-mail: cqupcc@163.com.

通讯作者:

王成龙(通信作者),男,副教授,E-mail: wangclong@cqu.edu.cn。

中图分类号:

TU445

基金项目:

国家自然科学基金(51908087);重庆市“博士后创新人才支持计划”(CQBX201903);中央高校基本科研业务费(2021CDJQY-042);中国博士后科学基金(2019M663439)


Displacement characteristics of energy piles in seasonally frozen regions
Author:
Affiliation:

1.College of Civil Engineering;2.Key Laboratory of New Technology for Construction of Cities in Mountain Area, Ministry of Education, Chongqing University, Chongqing 400045, P. R. China

Fund Project:

National Natural Science Foundation of China (No. 51908087); Chongqing Postdoctoral Innovative Talents Support Program (No. CQBX201903); Fundamental Research Funds for the Central Universities (No.2021CDJQY-042); China Postdoctoral Science Foundation (No. 2019M663439)

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    摘要:

    能量桩是一种既可以与土体进行能量交换,又可以承担上部荷载的桩基形式。上部土层冻结,下部土层未冻结,由温度变化引起的桩体自身变形及土体的冻胀融沉引发的桩体位移是能量桩在季节性冻土地区推广中亟待解决的主要问题。针对季节性冻土地区土体温度分布特点,将土体分为冻结层和非冻结层分别开展模型试验,测得冻结层和非冻结层中能量桩多次温度循环后的桩—土温度分布、桩周土体孔隙水压力及桩体位移的变化规律。结果表明:在非冻结土层中,多次循环取热后桩顶会产生不可逆的沉降位移,5次取热循环后,桩顶沉降达到0.95%DD为桩体直径),且桩体沉降未达到稳定;在冻结层,放热过程中能量桩会发生桩体融沉现象,恢复过程中会发生桩体冻胀现象,融沉导致的沉降位移随着循环次数的增加逐渐减小,在第3轮放热循环后消失。第1、2、3轮的融沉位移分别为5.9%D、0.93%D、0.11%D。每轮循环过程中,冻胀引起的上升位移虽逐轮减小,但在5轮循环之后依旧存在,且冻胀引发的总位移呈阶梯状上升,桩体最终产生上升位移,达到3.8%D

    Abstract:

    Energy pile is a type of structure which can not only exchange energy with soil, but also bear the upper loading. In the seasonal frozen soil area, the upper soil layer would be frozen, and the soil in the lower part would not. The thawing settlement, frosting heave and self-deformation of the pile caused by temperature variation are the main problems to be solved for application of energy piles in this area. According to the distribution characteristics of ground temperature in seasonal frozen soil areas, the soil was divided into frozen layer and non-frozen layer, and the model tests were carried out respectively. The pile and soil temperature distribution, pore water pressure of the soil surrounding the pile and pile displacement after multiple temperature cycles in frozen and non-frozen layers were measured. The results show that irreversible settlement of the pile top would occur after multiple cycles of heat extraction in the non-frozen soil area. After 5 cycles of heat extraction, the settlement of the pile top reached 0.95%D (D is the diameter of the pile), while the settlement of the pile would not reach stable state. In the frozen layer, thawing settlement of the pile would occur in the heat injection process, and frosting heave of the pile would occur in the recovery process. The settlement caused by thawing gradually decreased with increase of thermal cycles, and disappeared after the 3rd heat injection cycle. The thawing settlement of the pile after the 1st, 2nd and 3rd heat injection reached 5.9%D, 0.93%D and 0.11%D, respectively. During each cycle, although the rising displacement caused by frosting heave decreased in each following cycle, it still existed after 5 cycles, and the displacement caused by frosting heaving rose is of a ladder shape. The pile heave was produced in the end and reached 3.8%D.

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引用本文

彭宸,王成龙,丁选明,陈志雄.季节性冻土区能量桩位移变化规律[J].土木与环境工程学报(中英文),2023,45(2):65-73. PENG Chen, WANG Chenglong, DING Xuanming, CHEN Zhixiong. Displacement characteristics of energy piles in seasonally frozen regions[J]. JOURNAL OF CIVIL AND ENVIRONMENTAL ENGINEERING,2023,45(2):65-73.10.11835/j. issn.2096-6717.2022.070

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  • 收稿日期:2022-01-12
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  • 在线发布日期: 2023-03-20
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