Device and method for quickly measuring soil-water characteristic curve by considering dynamic load and lateral confinement

Abstract

The invention discloses a device and a method for quickly measuring a soil-water characteristic curve by considering dynamic load and lateral confinement. The device consists of a pressure control system, a vertical pneumatic dynamic loading system, a lateral air bag restraint system, a pressure chamber system and a water volume measurement system. The output end of the pressure control system isconnected with an air inlet of the vertical pneumatic dynamic loading system, and a computer is electrically connected with the control end of the vertical pneumatic dynamic loading system and used for controlling dynamic loading of the vertical pneumatic dynamic loading system. The lateral air bag restraint system comprises a sleeve which sleeves the side surface of a soil sample, a closed annular air bag is arranged between the sleeve and the soil sample, and the annular air bag is connected with the output end of the pressure control system through an air pipe and used for controlling the air pressure of the annular air bag. The dynamic load borne by the soil sample in a real state can be better simulated, the measurement efficiency is high, the measurement error is small, and the accuracy is higher.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering, and relates to a device and method for quickly measuring soil-water characteristic curves in consideration of dynamic loads and side limits. Background technique [0002] The soil-water characteristic curve refers to the relationship curve between the soil matric suction and the soil moisture content, saturation or volumetric moisture content. The soil-water characteristic curve is an important part of the constitutive model of unsaturated soil, which can be used to estimate the strength and permeability coefficient of subgrade soil, and is also a key parameter and basic test content in unsaturated soil mechanics. However, the current test technology has shortcomings such as single stress state, long experiment time, low level of automation, inaccurate data collection, and difficult judgment of suction balance conditions. [0003] Subgrade soil has a certain filling height and i...

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Problems solved by technology

However, the added stress is a single vertical static load, which cannot better describe the properties of the subgrade soil under the true stress state

In the test of measuring the soil-water characteristic curve using the stress-related soil-water characteristic curve pressure plate instrument, the permeability of the clay plate to the water flow is extremely low, about 1×10 -11 , It takes a lot of time to balance the matric suction of the soil sample when measuring the soil-water characteristic curve (SWCC) with a high air intake value clay plate. When measuring the soil-water characteristic curve, it takes about 7 days for each test point to reach the suction The balance of each soil-water characteristic curve usually takes 1 to 2 months, and the test balance suction time is relatively long; part of the air diffuses through the clay plate with high air intake value, and tends to gather under the clay plate. This leads to inaccurate measurement of the water volume discharged from the soil sample; during the experiment, the hose of the water volume measurement system is prone to intermittent air bubbles, while the existing equipment uses a small hand pump to give the water volume measurement system a vacuum value or pressure value, making the air bubbles It is discharged to the air collecting pipe, and in the long-term balance process, it needs to continuously diffuse the air bubbles, the manual operation is complicated and difficult to control

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