Device for testing saturated permeability coefficient in situ

Abstract

The utility model belongs to the technical field of soil permeability detection, and discloses a device for in-situ testing of a saturated permeability coefficient. Comprising a penetration device and a seepage water amount reading device, the penetration device is used for penetrating into a set position of a soil layer, and the seepage water amount reading device is installed above the penetration device and used for adding water and reading the seepage water amount; the penetration device comprises a penetration cutting ring, a top cover and a compaction hammer, the top cover is arranged at the top of the penetration cutting ring, the detachable center-penetrating compaction hammer is arranged on a top cover rod, the penetration cutting ring penetrates into a set position of a soil layer under the action of the compaction hammer, and the test device is small in occupied space, convenient to carry, low in site requirement and high in test efficiency. The device is simple in structure and convenient to use, is suitable for various narrow or uneven sites such as side slopes and road shoulders, brings convenience to field tests, is small in water consumption, and can carry a certain amount of water for tests under the condition that no water source exists or the water amount is limited.

Description

Technical Field

[0001] The utility model belongs to the technical field of soil permeability performance detection, and particularly relates to a device for in-situ testing of saturated permeability coefficient. Background Technique

[0002] The saturated permeability coefficient is an important parameter reflecting the permeability performance of soil, and is a parameter that must be measured in seepage calculation and permeability control in engineering. Its accuracy and reliability are of great significance for ensuring engineering safety. The existing methods of permeability tests mainly include two categories: laboratory tests and in-situ tests.

[0003] Laboratory tests are respectively constant head tests and variable head tests. Constant head tests are suitable for measuring sandy soils with high permeability, and variable head tests are suitable for measuring soils with relatively small permeability coefficients. These two test methods are simple and convenient to operate. Samples can be taken on-site and then brought back to the laboratory for testing, reducing the field workload. However, laboratory tests have deficiencies in both sample preparation and reliability. In terms of sample preparation, it is sometimes difficult to obtain complete undisturbed block samples on-site. In addition, the disturbances generated during transportation and indoor cutting processes all affect the measured permeability coefficient. In terms of reliability, the permeameter ring used in laboratory tests has a small scale, and the soil samples taken are often insufficient to represent the permeability under a larger scale range in the field. On the other hand, usually fewer block samples are taken to reduce the field sampling workload, and the discrete situation of the in-situ soil permeability coefficient cannot be well reflected in terms of reliability.

[0004] Compared with laboratory permeability tests, the testing process of in-situ permeability tests is closer to the actual seepage process of soil layers. Currently, the existing in-situ permeability tests are usually double-ring tests. This method takes a long time and consumes a large amount of water, and is not convenient to implement for slope sites and water-scarce field environments. Moreover, the double-ring permeameter usually measures the saturated permeability coefficient representing a depth range of 1 m, and is not suitable for soil layers with large void ratio changes with depth. Therefore, there is an urgent need for a device for in-situ testing of saturated permeability coefficient. Content of the Utility Model

[0005] The purpose of the utility model is to provide a device for in-situ testing of saturated permeability coefficient to solve the problems of large water consumption, long time consumption, and inapplicability to slope sites in the existing in-situ double-ring test.

[0006] To achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A device for in-situ testing of saturated permeability coefficient includes a penetration device and an infiltration water reading device. The penetration device is used to penetrate into a set position of the soil layer, and the infiltration water reading device is installed above the penetration device and is used to add water and read the infiltration water volume.

[0008] The penetration device includes a penetration cutter, a top cover, and a compaction hammer. The top cover is arranged on the top of the penetration cutter, and the compaction hammer is detachably arranged on the top cover. The penetration cutter penetrates into a set position of the soil layer under the action of the compaction hammer.

[0009] Preferably, the penetration cutter is a cutter with an inner diameter of 10 cm, a height of 10 cm, and a wall thickness of 0.15 cm, and its lower edge is provided with a cutting edge.

[0010] Preferably, the penetration cutter is a stainless-steel cutter.

[0011] Preferably, a vertical rod is arranged at the center of the top cover, and the compaction hammer is sleeved outside the vertical rod.

[0012] Preferably, an exhaust hole is also opened on the top cover.

[0013] Preferably, the infiltration water volume reading device includes an observation tube. A docking port is arranged below the observation tube. The docking port is adapted to the penetration cutter, and scale lines for reading are arranged on the wall of the observation tube.

[0014] Preferably, a conical transition body is arranged inside the docking port.

[0015] Preferably, a sealing device is further included, and the sealing device is arranged around the docking part of the penetration cutter and the infiltration water volume reading device.

[0016] Preferably, the observation tube is an organic glass tube, and organic glass tubes with different inner diameters are provided for selecting organic glass tubes with different specifications according to test conditions.

[0017] Preferably, the docking port is 1 cm high, and 0.5 cm of it can be embedded in the penetration cutter.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] 1) Compared with the indoor penetration test device, the test device has a simpler structure and is easier to operate, avoiding the disturbance to the transportation and sampling of undisturbed soil. It can be tested multiple times in different areas on site, and the obtained permeability coefficient is more reliable.

[0020] 2) The infiltration core cutter 1 has a moderate size, which is larger than the core cutter with a diameter of 6.18 cm used in indoor tests, and has better representativeness. Moreover, there is no disturbance problem caused by cutting samples during transportation and testing. This size is smaller than that of the double-ring infiltrometer, and a large amount of water can be saved in the infiltration test, which has obvious advantages in an environment with insufficient water sources, and the testing time is greatly shortened. The infiltration core cutter is equipped with a cutting edge and can easily penetrate into the in-situ soil. The measured infiltration coefficient can better represent the infiltration coefficient of the penetrated soil part. While the double-ring infiltrometer usually measures the saturated infiltration coefficient within a depth range of 1 m. Therefore, this device has better applicability for soil layers with large void ratio changes with depth. Overall, this test device is simple, can be disassembled and assembled, and is more suitable for carrying than the double-ring infiltrometer. Compared with measuring the infiltration coefficient with a double-ring infiltrometer, this test device occupies less space, is convenient to carry, has low requirements for the site, is applicable to various narrow or uneven sites such as slopes and road shoulders, which brings convenience to field tests. And this device uses less water, and even in the case of no water source or limited water volume, it can also conduct tests by carrying a certain amount of water.

[0021] 3) It is applicable to soils with different infiltration properties. According to the high or low permeability, different inner diameter plexiglass tubes are selected to obtain a reliable infiltration volume-time curve, and the overall test takes a short time. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural view of the penetration device of the in-situ test simple device for the saturated infiltration coefficient of the present invention.

[0024] Figure 2 It is a schematic structural view of the infiltration water volume reading device of the in-situ test simple device for the saturated infiltration coefficient of the present invention.

[0025] Figure 3 It is an overall schematic view of the in-situ test simple device for the saturated infiltration coefficient of the present invention.

[0026] Wherein: 1 - infiltration core cutter; 2 - cutting edge; 3 - top cover; 4 - vertical rod; 5 - compaction hammer; 6 - exhaust hole; 7 - conical transition body; 8 - plexiglass observation tube; 9 - scale line; 10 - rubber membrane. Detailed Embodiments

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. The components of the embodiments of the present utility model described and illustrated herein can be arranged and designed in various different configurations.

[0028] Therefore, the detailed description of the embodiments of the present utility model provided in the accompanying drawings is not intended to limit the scope of the claimed present utility model, but merely represents selected embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0030] In the description of the embodiments of the present utility model, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships in which the utility model product is customarily placed during use, it is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0031] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0032] In the description of the embodiments of the present utility model, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "connected to" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] The following further describes the present utility model in detail with reference to the accompanying drawings:

[0034] See Figures 1 to 3 , this application discloses a device for in-situ testing of saturated permeability coefficient, which includes a penetration device and a water infiltration volume reading device. The penetration device is used to penetrate into a set position of the soil layer, and the water infiltration volume reading device is installed above the penetration device and is used to add water and read the infiltration water volume;

[0035] The penetration device includes a penetration cutter ring 1, a top cover 3 and a compaction hammer 5. The top cover 3 is arranged at the top of the penetration cutter ring 1, and the compaction hammer 5 is detachably arranged on the top cover 3. The penetration cutter ring 1 penetrates into the set position of the soil layer under the action of the compaction hammer 5. During on-site tests, first use the compaction hammer 5 to drive the penetration cutter ring 1 into the soil by 8 cm, and then connect the water infiltration volume reading device. After adding water, the water infiltration volume reading device can also be used to read the infiltration water volume. This test device occupies a small space, is easy to carry, has low requirements for the site, and is suitable for various narrow or uneven sites such as slopes and road shoulders, which brings convenience to field tests. Moreover, this device uses less water. In the case of no water source or limited water volume, tests can also be carried out by carrying a certain amount of water. It is applicable to soils with different permeability properties. According to the level of permeability, different inner diameter plexiglass tubes are selected to obtain a reliable infiltration volume-time curve, and the overall test takes a short time.

[0036] In some embodiments, a device for in-situ testing of saturated permeability coefficient includes a penetration device and a water infiltration volume reading device. The penetration device includes a permeation cutter ring 1 with an inner diameter of 10 cm and a height of 10 cm. During on-site tests, first use the compaction hammer 5 to drive the penetration cutter ring 1 into the soil by 8 cm, and then connect the water infiltration volume reading device. After adding water, the water infiltration volume reading device can also be used to read the infiltration water volume. The size of the permeation cutter ring 1 is moderate, larger than the diameter of the cutter ring (6.18 cm) used in indoor tests, and has better representativeness. Moreover, there is no disturbance problem caused by cutting samples during transportation and testing. This size is smaller than the size of the double-ring infiltrometer. The infiltration test can save a large amount of water, and it has obvious advantages in an environment with insufficient water sources, and the test time is greatly shortened. The permeation cutter ring is equipped with a cutting edge and can easily penetrate into the in-situ soil. The measured permeability coefficient can better represent the permeability coefficient of the penetrated soil part, while the double-ring infiltrometer usually tests the saturated permeability coefficient representing a depth range of 1 m. Therefore, this device has good applicability for soil layers with large void ratio changes with depth. Overall, this test device is simple, can be disassembled and assembled, and is more suitable for carrying than the double-ring infiltrometer.

[0037] In some embodiments, a device for in-situ testing of saturated permeability coefficient includes a penetration device and a water infiltration volume reading device. The penetration device is used to penetrate into a set position of the soil layer, and the water infiltration volume reading device is installed above the penetration device for adding water and reading the water infiltration volume. The penetration device includes a penetration cutter ring 1, a top cover 3, and a compaction hammer 5. The top cover 3 is arranged on the top of the penetration cutter ring 1, and the compaction hammer 5 is detachably arranged on the top cover 3. The penetration cutter ring 1 penetrates into the set position of the soil layer under the action of the compaction hammer 5. The penetration cutter ring 1 is a stainless steel cutter ring with an inner diameter of 10 cm, a height of 10 cm, and a wall thickness of 0.15 cm. There is a cutting edge at the lower edge of the cutter ring, which is convenient for pounding into the soil. A top cover 3 is provided to match the lower penetration cutter ring 1. There is a vertical rod 4 with a height of 30 cm in the center of the top cover 3. The compaction hammer 5 can move along the direction of the vertical rod 4, which is convenient for vertically and evenly driving the penetration cutter ring 1 into the soil body. There is also an exhaust hole 6 on the top cover 3.

[0038] The water infiltration volume reading device includes an observation tube 8. A mating interface is provided below the observation tube 8, and the mating interface is adapted to the penetration cutter ring 1. Scale lines 9 for reading are provided on the wall of the observation tube 8. The observation tube 8 is a hollow plexiglass tube with a variable cross-section and both ends open, and its height is 31 cm. The mating interface at its lower part is 1 cm high, and 0.5 cm of it can be embedded in the penetration cutter ring 1. After connection, it has the same inner diameter as the penetration cutter ring 1. A conical transition body 7 is arranged inside the mating interface. The inner cross-section of the conical transition body 7 gradually decreases from bottom to top, which is convenient for bubble removal. The upper 30 cm of the observation tube 8 is a water level observation tube with an equal cross-section. The wall of the observation tube 8 is provided with a scale with a graduation value of 0.1 cm along the vertical direction. The observation tube 8 is a plexiglass tube, and its inner diameter has different specifications. During the test, the lower cutter ring is driven into the soil. According to the properties of the measured soil sample, an observation tube 8 with a suitable inner diameter is selected. The water infiltration volume reading device is sleeved on the penetration cutter ring 1, wrapped with a latex film, and tied tightly with a rubber band above and below the interface. Then water is poured in until the time used for the same infiltration height is very close. It can be considered that the tested soil body is saturated, and then the formal permeability test can be carried out, and the saturated permeability coefficient is calculated using the variable head formula.

[0039] As Figure 1 shown, the penetration process device consists of a permeation cutter ring 1, a top cover 3, a vertical rod 4, a compaction hammer 5, and an exhaust hole 6. By moving the compaction hammer 5 along the vertical rod 4, the cutter ring 1 can be evenly driven into the soil body, reducing the damage to the soil body during the penetration process.

[0040] As Figure 2 shown, the upper water infiltration volume reading device consists of a conical transition body 7, an observation tube 8, and scale lines 9. The conical transition body 7 can be a bubble discharge device.

[0041] As Figure 3 shown, after connecting the observation tube 8 and the cutter ring 1, a latex film is used to cover the connection part and tied with rubber bands above and below the interface to form a sealing device 10 to prevent water leakage during the permeability test.

[0042] Working principle:

[0043] Level the soil in the area to be measured, horizontally place the penetration ring cutter 1 on the soil, dock the top cover 3 on the ring cutter, lift the compaction hammer 5, and vertically hammer the penetration ring cutter 1 along the vertical rod 4 to ensure that the penetration ring cutter 1 slowly and vertically penetrates into the soil to the specified depth, and remove the compaction top cover 3; evenly apply vaseline at the interface, insert the base part of the observation pipe 8 into the top of the penetration ring cutter 1. During the docking process, the upper part should be kept vertical to avoid disturbing the soil inside the penetration ring cutter 1. Use a latex film outer sleeve at the docking part and tie rubber bands above and below the interface to form a sealing device 10 to prevent water from flowing out of the docking place; slowly inject water into the device through the upper opening of the observation pipe 8, and avoid scouring the soil inside the ring cutter 1; when the seepage is basically stable, that is, when the lower soil is basically saturated, fill the observation pipe 8 with water, record the relationship between the water head position and time, and calculate the saturated permeability coefficient using the variable head formula.

[0044] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-situ testing device for saturated permeability coefficient, characterized in that, It includes a penetration device and an infiltration water volume reading device. The penetration device is used to penetrate into a set position of the soil layer, and the infiltration water volume reading device is installed above the penetration device and is used to add water and read the infiltration water volume. The penetration device includes a penetration cutter ring (1), a top cover (3) and a compaction hammer (5). The top cover (3) is arranged at the top of the penetration cutter ring (1), and the compaction hammer (5) is detachably arranged on the top cover (3). The penetration cutter ring (1) penetrates into the set position of the soil layer under the action of the compaction hammer (5).

2. The device for in-situ testing of saturated permeability coefficient according to claim 1, wherein, The penetration cutter ring (1) is a cutter ring with an inner diameter of 10 cm, a height of 10 cm and a wall thickness of 0.15 cm, and a cutting edge (2) is provided at its lower edge.

3. The device for in-situ testing of saturated permeability coefficient according to claim 2, characterized in that, The penetration cutter ring (1) is a stainless steel cutter ring.

4. The device for in-situ testing of saturated permeability coefficient according to claim 1, characterized in that, A vertical rod (4) is arranged at the center of the top cover (3), and the compaction hammer (5) is sleeved outside the vertical rod (4).

5. The device for in-situ testing of saturated permeability coefficient according to claim 1, characterized in that, An exhaust hole (6) is also opened on the top cover (3).

6. The device for in-situ testing of saturated permeability coefficient according to claim 1, characterized in that, The infiltration water volume reading device includes an observation tube (8). A docking interface is arranged below the observation tube (8), and the docking interface is adapted to the penetration cutter ring (1). Scale lines (9) for reading are arranged on the wall of the observation tube (8).

7. The device for in-situ testing of saturated permeability coefficient according to claim 6, characterized in that, A conical transition body (7) is arranged inside the docking interface.

8. The device for in-situ testing of saturated permeability coefficient according to claim 1, characterized in that, It also includes a sealing device (10), and the sealing device (10) is arranged around the docking part of the penetration cutter ring (1) and the infiltration water volume reading device.

9. The device for in-situ testing of saturated permeability coefficient according to claim 6, characterized in that, The observation tube (8) is an acrylic tube, and acrylic tubes with different inner diameter specifications are provided for selecting acrylic tubes with different specifications according to the soil permeability.

10. The device for in-situ testing of saturated permeability coefficient according to claim 6, characterized in that, The docking interface below the observation tube (8) is 1 cm high, and 0.5 cm of it can be embedded in the penetration cutter ring (1).

Images