复杂受力条件下重力式结构基底应力的实测研究

以大跨径悬索桥的锚碇工程为例,阐述了岩质地基上重力式结构的受力特点及其基底应力监测的意义和方法．根据132个应力测点在4a内的88次实测资料,分析重力式锚碇的传力机理．研究成果表明,在巨大上拔力和水平向拉力作用下,锚碇基底应力的变化过程是复杂的．在主缆力施加的初期,锚块后侧基底应力即呈下降趋势,而前侧则具有支点的作用,基底应力呈上升趋势,但随着主缆力的增大,锚块前侧的支点作用丧失．鞍部基底应力变化过程类似于锚块,但不同步．锚碇前侧水平向抗力几乎与基底摩阻力同时逐渐发挥,所以,虽然锚碇的抗滑稳定具有较大的安全储备,但锚碇前侧抗力体仍需承受较大的水平推力．

Monitoring data-based study on foundation stress of gravity structures under complex loading conditions

With the anchorage project of a long suspension bridge as an example, the stress characteristics of the gravity structure on rock foundations and the significance and methods of monitoring of the foundation stress are expounded. According to the observation data of 88 times' monitoring at 132 stress observation points during 4 years, the mechanism of load transfer in the gravity embedded anchorage is analyzed. The results show that the variation of the stress in anchorage foundations is complex under the action of huge uplift and horizontal tensile forces. At the early stage of application of the main cable force, the stress in the rear section of the anchorage foundation shows a trend of decrease, while the stress in the front section of the foundation increases because of the fulcrum function of the fore anchorage. With the increase of the main cable force, the fulcrum function of the fore anchorage is gradually lost. The variation of the stress in the saddle foundation is similar to but nonsynchronous with that in the anchorage. Owing to the nearly simultaneous actions of the horizontal resistance on the front section of the anchorage and the friction along the foundation, the fore anchorage must bear the large horizontal thrust, although there is a large margin of safety for stability against sliding of the anchorage.