复杂荷载作用下桩基承载特性模型试验系统研发

Development of Model Test Equipment for Piles under Complex Loading Conditions

自主研发了复杂荷载作用下桩基承载特性模型试验系统,可开展单向荷载、竖向-水平耦合荷载作用下桩基加载试验。由模型槽、竖向-水平耦合加载系统、测量系统三部分构成,子系统之间以螺栓连接,可拆解。模型槽由透明有机玻璃制作、角钢加箍,便于试验土体观察和模型桩埋深、仪器埋设控制;加载系统采用滑轮、配重块和微型千斤顶、液压泵施加竖向-水平耦合荷载,设置直线滑动导轨为荷载方向调节装置,以消除水平面内桩顶与微型千斤顶之间摩擦力对桩土的作用效应,维持竖向力始终作用在桩顶中心位置;测量系统除可测得桩顶水平位移、沉降等数据外,亦可多点测量桩身水平挠曲线。最后开展了单向荷载、竖向-水平耦合荷载作用下PCC桩承载特性模型试验,对试验系统的可靠性和稳定性进行了验证。

A model test system for piles under complex loading conditions is independently developed,which can simulate pile bearing characteristics under single or vertical-horizontal coupling loads. The equipment comprises a model chamber,vertical-horizontal coupling loading system and measuring system. Each part is connected by bolts and can be removed. The model chamber is made of colourless transparent organic glass plates and angle iron,which helps to observe the test soil and the embedment depth ofmeasure instruments and model pile. The verticalhorizontal coupling loading system contains a linear slide rail,which can eliminate the effect of friction between the pile top and the mini jack in the horizontal plane and maintain vertical force at the center of the pile,and the system uses pulley,weights and mini jack,hydraulic pump applied vertical-horizontal coupling loads. Measurement system can measure the horizontal displacement,settlement,angle of pile top,bending moment of pile,lateral earth pressure,and can also measure the level of pile body horizontal deflection curve. Finally,the bearing capacity tests of PCC pile under unidirectional load and vertical-horizontal coupling loads are carried out using this equipment,which verified the reliability and stability of the test system.