The present invention provides a system and method for real-time measurement of water content in soil in a geotechnical structure object, the system includes at least one probe, each probe includes a base and four hard probe needles to facilitate the probe needles to insert into a soil sample, each probe is respectively connected with one end of a signal wire; the four probe needles are mutually in parallel and uniformly fixed in the base, the top parts of the four probe needles extend out of the base; the system also includes a computer for data calculation, analysis and display; a voltage tester; an ac (alternating current) current source, a signal input port of the voltage tester is connected with the probe to detect voltage signals between the different probe needles, a signal output port is connected with the computer for transmission of test results to the computer, and the ac current source is connected with the probe to provide a measuring current to the probe. The probe can be directly inserted into the soil sample for real-time on-site measurement of the water content, and the test precision of the water content of the soil sample is greatly improved.

System and method for real-time measurement of water content in soil in geotechnical structure object

The invention discloses a measurement device based on a frozen soil unfrozen water migration rule. The measurement device comprises a container with openings in two ends, a controller, a plurality ofelectrode patches, a plurality of electrode connecting lines, low-temperature circulators, an upper computer, an external measurement device and a water injection module; the low-temperature circulators are mounted at the two ends of the container with the openings in the two ends, and perform temperature control on a frozen soil sample placed in the container; the controller controls the electrode patches to work and acquires an electric signal for measurement; the electrode patches acquire an input power supply signal or output the electric signal for measurement; the water injection moduleis connected with water injection holes of the low-temperature circulators and is used for injecting water into the container; the external measurement device is used for supplying power to the controller, providing the input power supply signal and acquiring the electric signal for measurement through the controller; and the upper computer controls the electrode patches and controls the low-temperature circulators to work. The invention further discloses a measurement method of the measurement device based on the frozen soil unfrozen water migration rule. The measurement device realizes the measurement of unfrozen water in frozen soil, and is simple and reliable and is convenient to use.

Nondestructive measurement device based on frozen soil water migration rule, and measurement method thereof

The invention discloses a TDR (time domain reflection) technology based real-time test probe and device for water content of a triaxial sample of unsaturated soil. The probe and the device can be used for testing the local water content of the sample in a triaxial test of the unsaturated soil in geotechnical engineering. The probe comprises a base layer (1), multiple flexible conductors (2) and a connector (3), has certain flexibility, can be horizontally mounted on the cylindrical sample for the triaxial test of geotechnical engineering in a winding manner, is located between the triaxial sample (10) and a rubber membrane (4), is connected with a TDR tester (9) through a wire (8) and can monitor the water content of a mounting part at any time in a triaxial test process of the unsaturated soil. The problem that the water content of a local position cannot be acquired in the triaxial test process of the unsaturated soil in the geotechnical engineering is solved.

Real-time test probe and device for water content of triaxial sample of unsaturated soil

Provided is an EC sensor which is capable of measuring a correct EC value, even if the surface of an arbitrary electrode is contaminated or short-circuited, and measuring EC values, with high sensitivity, for various kinds of objects to be measured. By means of an MCU 5, a measurement circuit 3 calculates, on the basis of an electric resistance R measured by applying a measurement voltage V between electrodes 41 to 49, EC values of the objects to be measured. The MCU 5 outputs an alternating current voltage signal as the measurement voltage V. This alternating current voltage signal is applied to a voltage division circuit, which is configured from a serial circuit of a resistor R and the electrodes 41 to 49, and is voltage-divided. The voltage-divided signal d is amplified by an operation amplifier 6, analog-to-digitally converted by the MCU 5, and used for the calculation of the EC value. First switches S11 to S19, by which the measurement voltage V is intermittently applied, are provided to one ends, respectively, of the electrodes 41 to 49, and second switches S21 to S29, by which the connection to the ground voltage is intermittently performed, are provided to the other ends, respectively. Each switch is intermittently connected and a plurality of arbitrary electrode pairs are selected by a control of the MCU 5.

Ec sensor and field management system using same

The invention discloses a VDP method for measuring an influence line of electrical resistivity or water content of cylindrical soil, and relates to the technical field of civil engineering. In order to realize the VDP method to test the electrical resistivity of cylindrical soil, the invention uses a VDP method for testing electrical resistivity and water content flat unit soil as the basis, and wields the help of ''conversion coefficient eta''and ''altitude effect influence line'', so as to successfully apply the VDP method to the test of electrical resistivity of cylindrical soil sample; and the method is applied to the test of soil moisture by using the derived ''universal moisture formula''.

VDP method for measuring influence line of electrical resistivity or water content of cylindrical soil

The invention discloses a tri-axial testing device for testing the water content distribution of a soil sample. The device comprises a constant current alternating current source, a dynamic voltage tester, a computer and a plurality of groups of sheet electrodes, wherein the sheet electrodes correspond to the layers of the columnar tri-axial soil sample; each group comprises four sheet electrodes which are sequentially adhered to the corresponding layer of the soil sample and a tri-axial membrane at an interval of 45 degrees along the circumferential direction of the corresponding layer of the soil sample; the farthest two sheet electrodes and the middle two sheet electrodes in each group are alternately connected with the two electrodes of the constant current alternating current source and the two input ends of the dynamic voltage tester; the output end of the dynamic voltage tester is connected with the computer. According to the device, the van der Pauw principle is used for dynamically measuring the water content of the soil sample in real time; due to the adoption of the flexible sheet electrodes, the influence on the mechanical properties of the soil sample is avoided, and the testing accuracy of the water content of the soil sample is greatly improved.

Zhu Xianghui

Papers

Tri-axial testing device for testing water content distribution of soil sample