Test method for determining unsaturated soil water characteristic parameters

A technology of characteristic parameters and test methods, which can be used in soil material testing, suspension and porous material analysis, measuring devices, etc., and can solve problems such as determination of soil water conservation curve and unsaturated permeability coefficient in three-way loading state

Inactive Publication Date: 2010-10-20
INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are no instruments and test methods for measuring soil-water retention curve and unsaturated permeability coefficient under three-dimensional loading state at home and abroad.

Method used

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  • Test method for determining unsaturated soil water characteristic parameters
  • Test method for determining unsaturated soil water characteristic parameters
  • Test method for determining unsaturated soil water characteristic parameters

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0011] Embodiment: the characteristic parameter of unsaturated soil moisture, i.e. the measuring method of soil water retention curve is as follows,

[0012] ①Remove the first air pressure line 11 from the air pressure pump 21, connect the first water pressure line 4 to the air pressure pump 21, close the first air pressure control valve 18 and the second air pressure control valve 22, start the air pressure pump 21, open The first water pressure control valve 7 and the second water pressure control valve 19 are pressurized to saturate the upper clay plate 14 and the lower clay plate 36 with water;

[0013] ②After the upper clay plate 14 and the lower clay plate 36 are saturated, close the air pump 21, connect the first hydraulic pipeline 4 with the vacuum pump 8, close the first hydraulic control valve 7 and the second hydraulic control valve 19, and turn off the first hydraulic pressure control valve 7 and the second hydraulic control valve 19. A pneumatic pipeline 11 is con...

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PUM

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Abstract

The invention relates to a test method for determining the unsaturated soil water characteristic parameters, which utilizes a test device to measure the soil water retention curve of soil body. The device mainly comprises a vertical displacement measuring meter 1, bolts 2, a pressurized shaft 3, a pressure chamber 12, a sample top cap 13, a fixed bolt 24 and a sample base 25. A second air pressure control valve 22 and a second water pressure control valve 19 are adjusted, and the sizes of the pore air pressure and pore water pressure in a sample are changed by a second air pressure sensor 23 and a second water pressure sensor 38, i.e. the size of matric suction s of the sample is changed; after the liquid level in a second volume water measuring tube 17 is stabilized, the change value of water quantity of inlet and outlet samples is read out to obtain a new water content of the sample w1 corresponding to matric suction s 1 so as to obtain a group of test data s1 and w1 on the soil water retention curve. The determination method has convenient use, high measuring precision, meets the requirements of three-dimensional stress, can measure the humidifying section and the dehumidifying section of the soil water characteristic curve, and is suitable for measuring the soil water retention curves of various soils in civil engineering.

Description

technical field [0001] The invention relates to a test method for measuring characteristic parameters of unsaturated soil moisture, which belongs to the technical field of civil engineering. Background technique [0002] Unsaturated soil is widely distributed in our country. The natural sedimentary soil widely distributed on the surface of the earth and the soil problems encountered in engineering construction are almost all unsaturated soil problems. Saturated soil in the true sense is rarely seen in engineering practice. This makes the study of unsaturated soil mechanics very realistic and practical. Hydraulic hysteresis is an important feature of unsaturated soil, and hydraulic hysteresis is usually manifested in the hysteresis of the soil-water retention curve, which is affected by many factors, such as soil structure, temperature and especially the stress state. Two important parameters used to describe the moisture characteristics of unsaturated soil are the correspon...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/08G01N33/24
Inventor 李志清胡瑞林
Owner INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI
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