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渗流作用下土层之间的接触面是较易发生渗透破坏的薄弱环节。在开展砂砾石渗透破坏试验研究的基础上,针对砂砾石与砂的接触面渗流及渗透破坏特性,利用大型竖向渗透仪和自主研制的环状径向水平渗透仪,研究了竖向和水平渗流作用下接触面渗流和渗透破坏的影响因素及接触冲刷的发生、发展过程。研究结果表明,典型的砂砾石与砂的接触冲刷破坏过程可分为稳定渗流阶段、过渡阶段和破坏阶段3个阶段,可用2个特征水力坡降进行划分,稳定渗流阶段与过渡阶段的分界点对应的水力坡降称为启动坡降,过渡阶段与破坏阶段的分界点对应的水力坡降称为破坏坡降;砂砾石与砂组合试样的渗透系数随砂砾石密度的增大、颗粒变细而减小,砂砾石与砂接触冲刷的抗渗坡降则随砂砾石密度的增大、颗粒变细而增大,在水平渗流情况下试样的渗透系数较竖向的大,但接触冲刷的抗渗坡降较竖向的小。
The contact surface between soils under seepage is the weak link that is prone to seepage and destructive. Based on the experimental study on sand and gravel infiltration and destructiveness, aiming at the seepage and seepage failure characteristics of gravel and sand, the vertical and horizontal Influencing factors of percolation and infiltration of seepage under seepage and the occurrence and development of contact erosion. The results show that the contact erosion process of sand and gravel can be divided into three phases, that is, stable seepage, transition and destruction, and can be divided by two characteristic hydraulic ramps, and the boundary between stable seepage and transition The corresponding hydraulic gradient is called the starting gradient. The hydraulic gradient corresponding to the boundary between the transition phase and the failure phase is called the descending slope. The permeability coefficient of the composite sample with gravel and sand increases with the density of gravel, Fine and small, sand and gravel and sand contact erosion scouring decline with the sand gravel density increases, the particles become thinner and larger, in the case of horizontal seepage flow permeability of the sample larger than the vertical, but the contact Scouring of the ramp is smaller than the vertical.