CN101692035A - Capillary soil water climbing height measuring device - Google Patents

Abstract

The invention relates to a soil capillary water rise height measuring device, which supplies a water source with a constant water level to the soil sample in the soil container by supplying a water source with a constant water level at the lower part of the soil container filled with soil samples, thereby It can accurately measure the rising speed, height and water content of capillary water corresponding to different soil samples, and provide basic data for the foundation design of highways, airports, dams and other projects, and can effectively prevent groundwater from immersing into the foundation. Keep the foundation soil in a relatively stable dry and wet state.

Description

A device for measuring the rising height of soil capillary water

technical field

The invention relates to a device for measuring the rising height of soil capillary water, which belongs to the technical field of geotechnical engineering testing.

Background technique

In the foundation design of highways, airports, dams and other projects, how to waterproof and keep moisture and keep the relative stability of soil moisture is a very critical issue. One of the factors that causes the change of the dry and wet state of the foundation soil is the capillary water penetration of the groundwater to the foundation soil. For example, the subgrade of a highway project is easily infiltrated by capillary water. Due to the rise of capillary water, the dry and wet state of the subgrade soil changes. , resulting in the strength reduction or instability of the subgrade, which in turn affects the strength and stability of the pavement structure. Therefore, it is necessary to prevent groundwater from infiltrating into the foundation during the design process. The control of water migration in subgrade soil is a key technical issue in the design of low subgrades.

At present, most of the research on the application of capillary water in my country is concentrated in the agricultural water conservancy department, and the research area is mostly limited to the soil salinization area and the seasonal freeze-thaw area. The relatively simple vertical pipe method is generally used to measure the rising height of capillary water , that is, the test is carried out after the soil sample is buried with a small-diameter circular tube. The device is relatively simple, and the measured capillary water rise height is not accurate enough.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a soil capillary water rising height measuring device, which supplies a water source with constant water level at the lower part of the soil holding cylinder filled with soil samples to measure the soil sample in the soil holding cylinder. Conduct capillary water infiltration to obtain more accurate capillary water rise height of soil samples, and provide basic data for foundation design of highways, airports, dams and other projects, which can prevent groundwater from infiltrating into the foundation as much as possible and keep the water content of the foundation soil relatively stable .

For realizing above technical purpose, the present invention takes following technical scheme:

A device for measuring the rising height of soil capillary water, comprising a soil holding cylinder for burying soil samples, a water holding base for supplying capillary water penetration of soil samples, and a water supply device with a constant water level, the two ends of the soil holding cylinder are open , which includes more than one section of the soil-filling cylinder, two adjacent soil-filling cylinders are connected by a flange, the upper end of the soil-filling cylinder is installed with a sealing cover, and the lower end of the soil-filling cylinder is installed on the base through the flange, The water holding base is provided with a water-permeable supporting part used in conjunction with the lower end of the soil holding cylinder for supporting the soil sample, and a plurality of through holes are axially spaced on the wall of the soil holding cylinder, and the water outlet end of the water supply device is connected to the Base water inlet connection.

The water supply device includes a water supply box and a chassis, an elastic supporting device is connected between the water supply box and the chassis, and the water supply box is connected with the water holding base.

More than one soil moisture velocity measuring instrument is embedded in the soil sample, and the probe wire of the soil moisture velocity measuring instrument is drawn out from the through hole.

A water level observation tube is arranged on the water holding base.

The permeable supporting part is a permeable stone, and the diameter of the permeable stone is smaller than the inner diameter of the soil holding cylinder.

A filter layer is arranged between the soil sample and the permeable stone.

A lubricating layer is arranged on the inner wall of the soil holding cylinder.

The inner diameter of the soil holding cylinder is 22-25 cm, the wall thickness is 8-10 mm, the diameter of the through hole is 2 cm, and the distance between two adjacent through holes is 5-10 cm.

The length of each section of the soil tube section is 45-70cm.

The elastic supporting device is composed of compression springs distributed in matrix form, and the two ends of the compression springs are respectively connected with the water supply tank and the chassis.

According to the above technical scheme, the following beneficial effects can be achieved:

1. The present invention supplies a water source with a constant water level at the lower part of the soil storage cylinder to infiltrate the soil samples in the soil storage cylinder by capillary water, so that the capillary water rise height corresponding to different soil samples can be measured more accurately , to provide basic data for the foundation design of highways, airports, dams and other projects, which can prevent groundwater from infiltrating the foundation as much as possible, and keep the foundation soil in a relatively stable dry and wet state;

2. The water holding base is made of metal, with a height of about 5cm. The diameter of the permeable stone is 5mm smaller than the inner diameter of the soil holding cylinder, which can support the pressure of the soil sample in the upper soil holding cylinder;

3. A small hole with the same diameter as the base is opened on one side of the side wall of the water supply tank, and a water guide pipe is connected externally to guide the water in the water supply tank into the bottom of the soil holding cylinder. A compression spring is installed at the bottom of the base. The water supply tank can rise to ensure the basic constant of the water level in the soil storage cylinder; the other side is connected with a glass water level observation tube for observing the water level in the test cylinder.

Description of drawings

Fig. 1 is the structural representation of capillary water rising device of the present invention;

Fig. 2 is a schematic structural view of the water supply device of the present invention;

Among them, soil holding cylinder section 1 through hole 11 soil moisture velocity measuring instrument 12 soil sample 13 flange plate 2 sealing cover 3 bolts 4 water holding base 5 water inlet pipe 51 water level observation pipe 52 permeable stone 53 chassis 61 elastic support device 62 water supply Box 63.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Fig. 1 and Fig. 2, the soil capillary water rising height measuring device according to the present invention includes a soil holding cylinder for filling the soil sample 13, a water holding base 5 for supplying the soil sample 13 capillary water penetration , and a water supply device with a constant water level, the two ends of the soil-filling cylinder are open, and it includes more than one soil-filling cylinder section 1, and the adjacent two soil-filling cylinder sections 1 are connected by flanges 2, which can be set according to needs. The soil-filling cylinders of different heights are fixed, and a sealing cover 3 is installed on the upper end of the soil-filling cylinder to prevent water from evaporating during the capillary water penetration process, causing inaccurate measurement of the penetration parameters of the soil sample 13, while the lower end of the soil-filling cylinder passes through the flange 2 Installed on the water holding base 5, the water holding base 5 is provided with a water permeable supporting part used in conjunction with the lower end of the soil holding cylinder for supporting the soil sample 13, the water permeable supporting part is a permeable stone 53, and the permeable stone 53 If the diameter is smaller than the inner diameter of the soil holding cylinder, the water in the water holding base 5 can pass through the permeable stone 53, thereby producing capillary infiltration to the soil sample 13, and the water holding base 5 is provided with a water level observation tube 52 to monitor different soils. The water supply of different water levels is set for the body sample 13, and a plurality of through holes 11 are provided at axial intervals on the wall of the soil holding cylinder, and more than one soil moisture velocity measuring instrument 12 is embedded in the soil sample 13. The probe wire of instrument 12 is drawn from through hole 11, and this through hole 11 can also be used for taking soil from the soil holding cylinder for testing. And the chassis 61, an elastic support device 62 is connected between the water supply tank 63 and the chassis 61, and the elastic support device 62 is composed of compression springs distributed in a matrix form, and the two ends of the compression spring are respectively connected with the water supply tank 63 and the chassis 61 .

A filter layer is provided between the soil sample 13 and the permeable stone 53, and the filter layer in the present invention is made of filter paper.

A lubricating layer is provided on the inner wall of the soil holding cylinder, on the one hand, it can be easily demolded, and on the other hand, it can effectively prevent the concentrated seepage on the cylinder wall from affecting the accuracy of the test results.

The soil holding cylinder is a colorless glass cylinder, which can facilitate the observation of soil color changes caused by the rise of capillary water; the diameter of the soil holding cylinder is controlled at about 22 to 25 cm, which can ensure that the soil sample 13 in the soil holding cylinder is convenient to operate, and The boundary effect when the capillary water infiltration occurs in the soil sample 13 in the soil holding cylinder can be ignored, and at the same time, the relative error of the capillary water rise caused by taking soil from the through hole 11 to test the water content of the soil sample 13 can also be ignored; The wall thickness is 8-10mm, which can ensure the strength of the soil holding cylinder and prevent damage during the test; the soil holding cylinder is divided into multiple sections, each section is controlled between 45-70cm, and the middle is fixedly connected by a flange plate 2, which can ensure The maximum degree of continuity of the soil storage cylinder is convenient for cleaning the soil in the cylinder after the test is over; the soil storage cylinder has through holes 11 with a diameter of about 2 cm in the wall of the cylinder every 5 to 10 cm, and each through hole 11 is equipped with rubber plugs. During the test, the hole distance can be set according to the needs. The 2cm hole diameter can not only dig out the soil to measure the water content of the soil, but also facilitate the lead wire of the probe when using the TDR test instrument.

When in use, connect the water holding base 5 and a soil holding cylinder section 1 with the flange 2 and screws, put the permeable stone 53 into the water holding base 5, and put a layer of filter paper on it to form a filter layer to prevent water penetration The stone 53 is in direct contact with the soil sample 13, and the wall of the soil holding cylinder section 1 is smeared with butter to form a lubricating layer. On the one hand, it can be easily demoulded, and on the other hand, it can prevent concentrated seepage on the wall from affecting the accuracy of the test results. Then, according to the designed degree of compaction, the prepared soil sample 13 is poured in, compacted evenly and layer by layer with a tamping hammer, and the hairs are chiseled between each layer, and the soil is buried at a predetermined height For the probe of the water velocity measuring instrument 12TDR, the wire protrudes from the through hole 11. When one section of the soil holding cylinder 1 is almost full, connect the other section of the soil holding cylinder 1 through the flange 2. According to this method Install the soil sample 13 and bury the TDR probe of the soil moisture velocity measuring instrument section by section to the designed test height, and install a sealing cover 3 after laying a plastic film on the top; On the water pipe, the height of the water level can be set according to the requirements, which can be adjusted through the water level observation tube 52. As the capillary water infiltration occurs in the soil sample 13, the water supply tank 63 will rise with the recovery of the compression spring, and the water level can be kept constant. The rise of capillary water can be judged by observing the color change of the soil through the soil holding cylinder; finally, according to the research needs, the water content of the soil sample 13 at different times and at different heights is set to be measured. In addition, if the soil is taken from the through hole 11 for For soil sample 13 water content measurement, the soil should be excavated from small to deep, and the soil should not be rotated to form large holes, so as to avoid the error of the result becoming larger.

Claims (10)

1. capillary soil water climbing height measuring device, it is characterized in that, comprise and be used to bury the soil-containing tube of body sample of banketing, supply with the base that is filled with water of soil body sample capillary water infiltration, and the constant water supply installation of water level, the soil-containing tube open at both ends is provided with, it comprises the soil-containing tube joint that a joint is above, connect by ring flange between the adjacent two soil-containing tubes joint, described soil-containing tube upper end is equipped with gland bonnet, the soil-containing tube lower end then is installed on the base by ring flange, be provided with the permeable support unit that is used to support soil body sample that is used with the soil-containing tube lower end in the described base that is filled with water, offer a plurality of through holes on the soil-containing tube wall, the water supply installation water side is connected with the base water inlet pipe by aqueduct axially spaced-apart.

2. capillary soil water climbing height measuring device according to claim 1 is characterized in that described water supply installation comprises supply tank and chassis, is connected with resilient supporting unit between supply tank and the chassis, and supply tank is connected with the base that is filled with water.

3. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that, is embedded with more than one soil moisture tacheometer in the soil body sample, and the probe lead of this earth moisture speed side instrument is drawn from through hole.

4. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that the base that is filled with water is provided with the water-level observation pipe.

5. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that, described permeable support component is a permeable stone, and this permeable stone diameter is less than the soil-containing tube internal diameter.

6. capillary soil water climbing height measuring device according to claim 5 is characterized in that, is provided with filtering layer between described soil body sample and the permeable stone.

7. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that the soil-containing tube internal face is provided with lubricating layer.

8. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that, described soil-containing tube internal diameter is 22～25cm, and wall thickness is 8～10mm, and the diameter of through hole is 2cm, and the spacing of adjacent two through hole is 5～10cm.

9. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that, the length of every joint soil-containing tube joint is 45～70cm.

10. capillary soil water climbing height measuring device according to claim 1 and 2 is characterized in that, the stage clip composition that described resilient supporting unit distributes for adopting matrix form, and the two ends of described stage clip are connected with the chassis with supply tank respectively.

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