Geotextile axial-compression clogging test device and method thereof

Abstract

The invention belongs to the field of geosynthetics testing and especiallly relates to a geotextile axial-compression clogging test device and a method thereof. A sample container includes a water tank, a retaining ring, a ring knife, water-permeable boards and a sample cover. The retaining ring, the water-permeable boards and the sample cover are successively placed into the water tank. A deformation measuring device and an axial pressurizing device are in contact with the sample. The ring knife is arranged between the top water-permeable board and the bottom water-permeable board. The axialpressurizing device is connected to the sample cover through a steel ball at the center of the top of the sample cover. The invention has the following beneficial effects: through the axial pressurizing device, water of a soil sample drives soil particles to migrate under the action of pressure so as to cause clogging of geotextile; then, the problem of a traditional gradient ratio method that hydraulic gradient must be provided by the use of an external water source, piezometric level is read and osmotic coefficient is calculated through water percolating capacity, there are errors between piezometric level and actual head, and it is difficult to measure clogging in blockage in low-permeability soil is solved; and the device also can be used for testing clogging characteristics under specific vertical pressure.

Description

technical field [0001] The invention belongs to the field of geotechnical synthetic material testing, and in particular relates to a geotextile axial compression clogging test device and method. Background technique [0002] Siltation means that when the geotextile is working, the small particles in the soil gather on the surface of the geotextile during the process of passing through the geotextile, or form a layer of impermeable water, or block the end of the filter channel of the geotextile, or stay in the geotextile. The interior of the fabric, resulting in a decrease in the water permeability of the geotextile. Clogging is usually assessed in terms of a decrease in water flow through the fabric, and an increase in soil particles entering the fabric. [0003] On the one hand, with the rapid development of my country's port engineering, waterway engineering and offshore engineering, a large number of soft soil foundations need to be reinforced. Soft soil foundations have...

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Problems solved by technology

In addition, as the water head of the piezometric tube increases, the seepage rate of water will also decrease; the longer it takes for the piezometric tube head to stabilize, the greater the impact of water evaporation on it

To sum up, when soils with low permeability coefficients such as silty clay and clay are used, the head stability time of the gradient ratio method is as long as several days, and the test period is long.

[0015] 2) It is difficult to accurately determine the stability of the reading of the piezometric tube

Due to the slow change of the water head of the piezometric tube and the influence of water evaporation, it is difficult to accurately judge whether the piezometric tube is stable. If the judgment is wrong, it will directly lead to an error in the calculation result of the gradient ratio

[0016] 3) Due to the long test time, when there are many fine particles in the soil, the nozzle of the piezometric tube is very easy to block

[0017] 4) Due to the existence of the above reasons, the water head of the piezometric tube at the same horizontal height often has a large difference in data, which brings some troubles to the selection of test data

[0018] 5) Gradient ratio method silting test requires saturated soil after sample loading. For low-permeability soil, the saturation speed is slow, and due to the low strength of the soil structure, the soil will be destroyed if it enters water a little faster, and the saturation is not easy. Control, if the saturation is not complete, the penetration rate will be reduced, which will have a significant impact on the test results

[0019] 6) The test water depends on the external water source, and the water head must be maintained during the test process, and a long test time will cause waste of water resources

Gradient ratio method clogging test, high reading frequency, low labor efficiency

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