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渗流是泥石流水动力条件主要来源之一,不同渗流流量具有不同的渗流力和冲刷力,从而可引起不同规模泥石流。通过开展室内水槽试验,利用测压管量测渗流过程中的孔隙水压力,并结合高清摄像技术从微观角度记录堆积土体内部细颗粒的运移、骨架颗粒的坍塌现象,以此分析研究土体渗透破坏、起动形成泥石流过程中的渗流和冲刷作用。在此基础上设定水槽坡度为7°,调节恒定渗流流量分别为120、170、265、320 ml/s,分析不同恒定渗流流量对固体堆积物失稳、泥石流起动过程中流态变化的影响。分析结果表明,在恒定渗流流量作用下,堆积土体内部细颗粒迁移、骨架颗粒坍塌造成土体颗粒重排列、孔隙水压力上升进而导致土体抗力降低是泥石流土体颗粒失稳、起动、冲刷的重要原因;随着渗流流量增加,流速迅速上升,土体内孔隙水压力逐步增大,骨架颗粒的失稳、移动主要受渗流及水流冲刷两方面共同作用,堆积土体颗粒的移动分别表现出缓慢小幅滑动后稳定、过渡型滑动和快速流滑现象。
Seepage flow is one of the main sources of debris flow hydrodynamic conditions. Different seepage flows have different seepage forces and flushing forces, which can cause debris flows of different scales. Through the indoor tank test, measuring the pore water pressure in the process of seepage flow by using the piezometer tube, and combining with the high-definition camera technology, the fine particle migration and the collapsing of skeleton particles are recorded from the microscopic point of view, Body penetration and destruction, start the formation of debris flow in the process of seepage and erosion. On this basis, the slope of the sink was set to 7 °, and the constant seepage flows were adjusted to 120,170,265,320 ml / s, respectively. The effect of different constant seepage flow on the instability of solid deposits and the flow regime during the start-up of debris flow was analyzed. The results show that under the action of constant seepage flow, the fine particles migrate inside the packed soil and the particles of the framework collapse cause the rearrangement of the soil particles. The increase of the pore water pressure leads to the decrease of the soil resistance, which is the instability of the soil particles in the debris flow, . As the seepage flow rate increases, the flow rate rapidly increases, the pore water pressure in the soil gradually increases, and the instability and movement of the skeleton particles are mainly affected by the seepage and water flow scouring. The movement of the accumulated soil particles respectively shows After a slight slow slide slowly, transitional sliding and rapid flow slip phenomenon.