考虑土体结构性损伤的静压桩承载力及时效性研究  

Study on the Bearing Capacity and Time Effect of Jacked Piles Considering Structural Damage of the Soil

作　　者：杨庆光[1] 李毛毛 王国锋 谢松 

机构地区：[1]湖南工业大学土木工程学院,湖南株洲412007 [2]中国水利水电第十四工程局有限公司,云南昆明650000

出　　处：《湖南工业大学学报》2017年第6期13-19,共7页Journal of Hunan University of Technology

基　　金：国家自然科学基金资助项目(51208194);湖南省自然科学基金资助项目(2016JJ2046)

摘　　要：考虑静压桩沉桩施工引起的桩侧土体结构性损伤,对Tresca屈服准则进行修正,并利用球孔扩张理论,得到考虑深度效应的极限扩孔压力的理论解。根据静压桩桩侧土体超孔隙水压力消散规律,结合Henkel理论,建立了考虑桩侧土体结构性损伤和深度效应的超孔隙水压力消散公式,并进一步得到土体地基中静压桩承载力与时间关系的计算公式。将按本方法计算的理论值与其他方法的计算结果以及实测值进行对比,验证了本方法的可靠性。在此基础上,进一步研究结构损伤系数和复压间隔时间等因素对静压桩桩侧超孔隙水压力的影响。结果表明:复压间隔时间越短,离桩中心距离越近,静压桩桩侧土中超孔隙水压力的消散速度越快,静压桩承载力越高;当径向损伤系数β_1已知,相同埋深处超孔隙水压力随着深度损伤系数β_2的增大而降低,且桩侧土体深度越深,β_2取值大小对孔隙水压力的影响越明显,从而进一步说明同时考虑土体径向和深度方向结构性损伤的必要性。In view of the structural damage done to the pile side soil by jacked piles, a modifcation has been made of the Tresca yield criterion. Based on the theory of spherical cavity expansion, the theoretical solution has thus been obtained of the limit reaming pressure considering the depth effect. According to the dissipation law of excess pore water pressure on the side soil of the jacked piles, combined with the Henkel theory, this paper seeks to establish the excess pore water pressure dissipation formula considering the structural damage and depth effect of the pile side soil, thus further obtaining the formula for calculating the relationship between the bearing capacity and the time of jacked piles in soil foundation. A comparison has been made between the theoretical values worked out by adopting this method and the calculated results and measured values yielded by other methods, thus verifying the reliability of the method. On this basis, a further study has been made of the infuence of the structural damage coeffcient and interval time on the excess pore water pressure of jacked piles. The results show that the smaller the distance between the pile and the pile center is, the faster the dissipation rate of the excess pore water pressure in the side of the jacked pile will be, and the higher the bearing capacity of the jacked pile will be as well; with the radial damage coeffcient β1 a known number, the excess pore water pressure in the same buried depth decreases with the increase of depth damage coeffcient β2, and the deeper the pile side soil is, the more obvious the infuence of the thus further verifying the necessity of taking into account the structural damage in the radial and depth directions of the soil simultaneously.

关 键 词：结构性损伤 球孔扩张 静压桩 超孔隙水压力 时效性 损伤系数 

分 类 号：TU471[建筑科学—结构工程]