双环注水试验装置的研制及其应用

针对现有双环注水试验装置在高渗透性土体中应用时的缺陷,研制了一套轮换注水式双环注水试验装置。该装置由注水系统和供水系统组成,巧妙地采用了在内环、外环中分别设置两组流量瓶向环内轮换注水,外接水箱向注空的流量瓶中供水的结构设计,保证了试验过程环内水头高度的稳定和连续注水。采用新研制的试验装置测试安哥拉格埃路地层(Quelo)棕红色砂土的渗透系数,获得了满意的应用效果。试验结果表明:安哥拉Quelo砂在天然状态下的渗透系数在10~(-3)~10~(-2) cm/s数量级,经压实后(重型击实试验控制,压实系数λ≥0.95)可降低1~3个数量级;在同一孔隙比下,现场双环注水试验结果高于室内变水头渗透试验结果约0.5个数量级。

Development and application of double-ring infiltrometer

In order to overcome the deficiency of the existing double-ring infiltrometer (DRI) for the soils with high permeability, a new DRI is developed. The device is composed of water injection system and water supply system. It only requires two sets of mariotte reservoirs for both the inner and outer cylinders to which, water can be added to the empty mariotte reservoirs from the external water tank when needed without affecting the measurements. The method keeps accurate constant head for high permeability and consecutive water supply during the testing process. The new DRI is used to test the permeability coefficient of Angola brown-red Quelo sand, and satisfactory results are achieved. The test results show that the permeability coefficient of Quelo sand in the natural state is 10^-3~10^-2 cm/s orders of magnitude, and after compaction (heavy compaction standard, compacting factor λ≥0.95) 1~3 orders of magnitude are reduced. The result of the in-situ double-ring water infiltration test is about 0.5 orders of magnitude higher than that of the indoor variable-head permeability test under the same void ratio.