CN106769786A - A kind of portable coarse-grained soil original position permeability test method - Google Patents

Abstract

The invention discloses a convenient coarse-grained soil in-situ infiltration test method, which comprises the following steps: excavating a test pit on the loose coarse-grained soil before rolling, and pre-burying a seepage ring into the test pit; Put it into the ring close to the inner wall of the infiltration ring, and make the outer edge around it expose the upper edge of the infiltration ring, backfill the soil on the geotextile until it is flush with the upper edge of the infiltration ring; carry out rolling so that the infiltration ring is Pressed into the coarse-grained soil layer, the outer edge of the geotextile is exposed to the ground; after the rolling is completed, the geotextile and its backfill soil are pulled out of the ground to form a measurement surface; the upper edge of the infiltration ring is excavated The rolled coarse-grained soil body of the ring is connected with the infiltration ring with a collar, and the gap between the two is filled with a water-stop sealing ring; a bracket is erected on the ground, and a water supply bottle is placed on the bracket, and the infiltration ring A gravel layer is laid at the bottom of the ring; a single-ring water injection test is carried out to calculate the soil permeability coefficient. Beneficial effect: the operation is simple and fast, and the measurement accuracy is high.

Description

A convenient in-situ penetration test method for coarse-grained soil

technical field

The invention relates to an in-situ infiltration test method, in particular to a convenient in-situ in-situ infiltration test method for coarse-grained soil, which belongs to the technical field of geotechnical tests.

Background technique

Coarse-grained soil refers to particles with a particle size greater than 0.075 mm and less than 60 mm. Coarse aggregate is an important material for earth-rock dam construction, and the measurement of its permeability is an important guarantee for the safe operation of the dam after construction. According to the "Geotechnical Test Regulations" (SL237-1999) and "Water Conservancy and Hydropower Engineering Drilling Water Injection Test Regulations" (SL345-2007), the in-situ penetration test usually adopts the test pit water injection method, which can be divided into single-loop water injection test and double-loop water injection test .

The single-ring water injection test in the test pit is suitable for sandy soil and sand pebble gravel soil layer, the double-ring water injection test is suitable for silt and clayey soil layers, and the single-ring water injection test for coarse-grained soil layer can be used to measure the permeability coefficient.

The single-ring water injection test must first dig a test pit on the coarse-grained soil layer after rolling, then dig out the water injection pit at the bottom of the test pit and put it into the single ring, and then use the water injection bottle to supply water to the ring to keep the water level in the ring constant. By measuring the amount of water infiltrated into the soil layer in the water supply bottle within a certain period of time, the soil permeability coefficient can be calculated.

The on-site test pit water injection test operation is very complicated. It is time-consuming and laborious to excavate the test pit on the coarse-grained soil layer after rolling. It is difficult to fit the excavated test pit with the ring, and it is easy to form a seepage channel around the ring. affect measurement accuracy. In addition, during the test, the problem that the ring is difficult to press into the coarse-grained soil layer due to bumping into the block stone often occurs. Therefore, it is of great practical significance and engineering significance to design an in-situ penetration test method that is simple and quick to operate, avoids excavating test pits on the solid coarse-grained soil layer after rolling, and can reduce the disturbance to the soil. value.

Contents of the invention

The main purpose of the present invention is to overcome the deficiencies in the prior art and provide a convenient in-situ penetration test method for coarse-grained soil. Excavating test pits is time-consuming and labor-intensive, and the soil is greatly disturbed, and the seepage ring is difficult to press into the coarse-grained soil layer after rolling.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A convenient coarse-grained soil in-situ penetration test method, comprising the following steps:

1) Before rolling, excavate a test pit on the loose coarse-grained soil, and bury the seepage ring in the test pit;

2) Put the geotextile close to the inner wall of the infiltration ring, and make the outer edge of the geotextile expose the upper edge of the infiltration ring, and then backfill the loose coarse-grained soil on the geotextile until the soil is backfilled The body is flush with the upper edge of the permeable ring;

3) Carry out rolling according to the corresponding filling standards of the actual project, so that the permeable ring is pressed into the coarse-grained soil layer, and the outer edge of the geotextile is exposed to the ground; The backfill soil is pulled out of the ground together to form the measurement surface for the penetration test;

4) Excavate the rolled coarse-grained soil around the upper edge of the seepage ring, and use a collar to connect with the upper edge of the seepage ring. The gap between the collar and the upper edge of the seepage ring The gap is filled with the upper water-stop sealing ring;

5) Set up a bracket on the ground, set the bracket above the infiltration ring, place a water supply bottle on the bracket, and lay a gravel layer at the bottom of the infiltration ring; use the water supply bottle to supply water to the infiltration ring, when the water supply bottle flows out After the water volume is stable, record the flow rate Q in the water supply bottle and the inner ring area A of the seepage ring for a period of time, and use the formula k=Q/A to calculate the soil permeability coefficient k .

The present invention is further provided that: the permeable ring is an iron ring.

The present invention is further set as: the thickness of the ring wall of the permeable ring is not less than 5 mm, and the diameter of the inner ring is 25 cm to 50 cm.

The present invention is further provided that: the geotextile is a geotextile.

The present invention is further set as follows: in the step 4), the rolled coarse-grained soil mass around the upper edge of the seepage ring is excavated, and the depth of the excavated soil mass is 5 cm.

The present invention is further set as: the diameter of the inner ring of the collar is larger than the diameter of the outer ring of the permeable ring by 3 mm to 5 mm.

The present invention is further provided that: the inner wall of the collar is provided with a groove, and the water-tight sealing ring is clamped in the groove.

The present invention is further provided that: the groove has two turns.

The present invention is further provided that: the water-stop sealing ring is a rubber ring.

Compared with prior art, the beneficial effect that the present invention has is:

1. The penetration test can be quickly carried out at the construction site, and the operation is simple. By pre-burying the penetration ring, the problem that the penetration ring is difficult to press into the coarse-grained soil layer in the later test can be avoided.

2. The infiltration ring and the coarse-grained soil layer can achieve better fit, avoiding the generation of infiltration channels around the infiltration ring.

3. It can avoid the time-consuming and labor-intensive problem of digging test pits on the solid coarse-grained soil layer after rolling, and at the same time reduce the disturbance to the soil.

The above content is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, the present invention will be further described below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is the schematic diagram that geotextile is put into along the infiltration ring inner wall in the embodiment of the present invention;

Fig. 2 is a schematic diagram of pre-embedded seepage ring and rolling in the embodiment of the present invention;

Fig. 3 is a schematic diagram of connecting the collar and the permeable ring in the embodiment of the present invention;

Fig. 4 is the sectional view of collar in the embodiment of the present invention;

Fig. 5 is a schematic structural view of a single-ring water injection test in an embodiment of the present invention.

detailed description

Below in conjunction with accompanying drawing of description, the present invention will be further described.

The present invention provides a kind of portable coarse-grained soil in-situ seepage test method, as shown in Fig. 1 to Fig. 5, comprises the following steps:

1) Before rolling, excavate a test pit on the loose coarse-grained soil, and bury the seepage ring 1 in the test pit; among them, the seepage ring is an iron ring, and the thickness of the ring wall is not less than 5mm 1. The diameter of the inner ring is 25cm~50cm. The strength of the penetration ring 1 used must ensure that it does not deform or deform very slightly when it is pressed into the soil.

2) As shown in Figure 1, put the geotextile 2 (such as geotextile) close to the inner wall of the permeable ring 1 into the ring, and make the outer edge of the geotextile 2 expose the upper edge of the permeable ring 1, and then place the The loose coarse-grained soil is backfilled on the geotextile until the backfilled soil 3 is flush with the upper edge of the infiltration ring 1, as shown in FIG. 2 .

3) Carry out rolling according to the corresponding filling standards of the actual project, so that the permeable ring 1 is pressed into the coarse-grained soil layer 4, and the outer edge of the geotextile 2 is exposed to the ground; after the rolling is completed, the geotextile 2 and The backfill soil 3 on the geotextile 2 is pulled out of the ground together to form a measurement surface for the penetration test. Wherein, the geotextile 2 used must have certain strength and flexibility, so as to ensure that the permeable ring 1 will not break when pulled out.

4) Excavate the rolled coarse-grained soil body with a longitudinal depth of 5cm near the outer circumference of the upper edge of the permeable ring 1, and use a collar 6 to connect with the outer circumference of the upper edge of the permeable ring 1. The collar 6 Fill the upper water-stop sealing ring 5 with the upper edge periphery of the permeable ring 1, as shown in Figure 3, the sealing performance is good, and it can ensure no water leakage; wherein, the diameter of the inner ring of the collar 6 is larger than that of the outer ring of the permeable ring. The diameter of the ring is 3mm~5mm, and the inner wall of the collar 6 is provided with two rings of grooves, and the water-stop sealing ring is a rubber ring clamped in the grooves, as shown in Figure 4, through the setting of the grooves, the sealing is further enhanced performance and installation firmness.

5) Set up a support 8 on the ground, erect the support 8 above the infiltration ring 1, place a water supply bottle 7 on the support 8, and lay a gravel layer 9 at the bottom of the infiltration ring 1; as shown in Figure 5, perform a single In the ring water injection test, the water supply bottle 7 is used to supply water to the permeation ring 1. When the water flow out of the water supply bottle 7 reaches a stable level, the flow Q in the water supply bottle 7 and the inner ring area A of the permeation ring 1 are recorded for a period of time. The formula k=Q/A calculates the soil permeability coefficient k .

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. a portable coarse-grained soil in-situ penetration test method, is characterized in that, comprises the following steps: 1) Before rolling, excavate a test pit on the loose coarse-grained soil, and bury the seepage ring in the test pit; 2) Put the geotextile close to the inner wall of the infiltration ring, and make the outer edge of the geotextile expose the upper edge of the infiltration ring, and then backfill the loose coarse-grained soil on the geotextile until the backfill soil The body is flush with the upper edge of the permeable ring; 3) Carry out rolling according to the corresponding filling standards of the actual project, so that the permeable ring is pressed into the coarse-grained soil layer, and the outer edge of the geotextile is exposed to the ground; The backfill soil is pulled out of the ground together to form the measurement surface for the penetration test; 4) Excavate the rolled coarse-grained soil around the upper edge of the seepage ring, and use a collar to connect with the upper edge of the seepage ring. The gap between the collar and the upper edge of the seepage ring The gap is filled with the upper water-stop sealing ring; 5) Set up a bracket on the ground, set the bracket above the infiltration ring, place a water supply bottle on the bracket, and lay a gravel layer at the bottom of the infiltration ring; use the water supply bottle to supply water to the infiltration ring, when the water supply bottle flows out After the water volume is stable, record the flow rate Q in the water supply bottle and the inner ring area A of the seepage ring for a period of time, and use the formula k=Q/A to calculate the soil permeability coefficient k . 2. A convenient in-situ in-situ seepage test method for coarse-grained soil according to claim 1, characterized in that: the seepage ring is an iron ring. 3. A portable coarse-grained soil in-situ seepage test method according to claim 1, characterized in that: the thickness of the ring wall of the seepage ring is not less than 5 mm, and the diameter of the inner ring is 25 cm to 50 cm. 4. A kind of portable coarse-grained soil in-situ penetration test method according to claim 1, characterized in that: the geotextile is a geotextile. 5. A kind of convenient coarse-grained soil in-situ seepage test method according to claim 1, characterized in that: in the step 4), the rolled coarse-grained soil around the upper edge of the seepage ring is excavated. Soil body, excavate the soil body to a depth of 5cm. 6. A convenient in-situ in-situ penetration test method for coarse-grained soil according to claim 1 or 3, characterized in that: the diameter of the inner ring of the collar is 3 mm to 5 mm larger than the diameter of the outer ring of the penetration ring. 7. A convenient in-situ penetration test method for coarse-grained soil according to claim 1, characterized in that: the inner wall of the collar is provided with a groove, and the water-stop sealing ring is clamped in the groove. 8. A convenient in-situ penetration test method for coarse-grained soil according to claim 7, characterized in that: the groove has two rings. 9. A convenient in-situ in-situ penetration test method for coarse-grained soil according to claim 1, characterized in that: the water-stop sealing ring is a rubber ring.