In-situ test device for testing hot melt settlement of frozen soil
By designing an in-situ testing device, which utilizes components such as steel pipes and drill rods to apply consolidation pressure and heat, the accuracy and economy issues of frozen soil thaw settlement testing were solved, achieving efficient and low-cost frozen soil thaw settlement testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2026-03-31
AI Technical Summary
Existing technologies for testing frozen soil thaw settlement suffer from sample disturbance and transportation errors in indoor tests, while field tests are time-consuming, labor-intensive, and expensive, making them difficult to conduct in high-altitude mountainous areas and affecting the accuracy of test results.
An in-situ test device for testing frozen soil thaw settlement is provided. By applying consolidation pressure and heat, and using components such as steel pipes, drill rods, conversion joints, copper pipes, and electric hot water tanks, drilling sampling, pressurization, and heating are achieved. The device has a simple structure, requires few materials, and is suitable for in-situ frozen soil thaw settlement tests.
It enables efficient and accurate in-situ testing of frozen soil thermal thaw settlement, avoiding sample disturbance, reducing test costs, and improving test success rate and accuracy.
Smart Images
Figure CN224066792U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of geotechnical engineering geotechnical testing, and in particular to an in-situ test device for testing the thermal thaw settlement of frozen soil, which is suitable for in-situ testing of the thermal thaw settlement of frozen soil with general properties such as clay, silt and sand. Background Technology
[0002] Thermal thawing hazards include thermal thawing of lakes and ponds, thermal thawing landslides or collapses, and thermal thawing subsidence and settlement. Among these, thermal thawing subsidence caused by the degradation of permafrost can not only lead to engineering geological hazard chains such as roadbed deformation and thermal thawing landslides, but may also have a significant impact on local hydrological processes and the ecological environment by altering the landform and microbial communities.
[0003] Testing the thaw settlement properties and mechanical parameters of frozen soil is a key focus of frozen soil engineering experiments. These tests are generally classified into two categories: laboratory tests and field tests. As suggested in the "Standard for Geotechnical Testing Methods GB / T 50123-2019," laboratory testing of frozen soil thaw settlement properties can be conducted through the frozen soil thaw compression test. The principle involves thawing the frozen soil under different consolidation pressures using a heated pressure plate, and then measuring the deformation caused by the thaw using a dial gauge. While this method is clear in principle and easy to operate, the need for on-site sample collection, transportation, and storage inevitably lead to sample disturbance, introducing errors to the test results and incurring additional costs.
[0004] Another type of field frozen soil thawing compression test is based on the same principle as the laboratory test, but the research object is a field test pit, and it requires jacks, concrete blocks, and a large-sized internally heated pressure plate (5000 cm2). Although the field test can preserve the in-situ stress of the soil under in-situ conditions, it is time-consuming, labor-intensive, expensive, and difficult to operate, making it difficult to conduct the test in high-altitude mountainous areas.
[0005] In summary, although indoor and field testing devices and methods for frozen soil thaw settlement exist, these methods have many limitations and affect the accuracy of the test results. Solutions to this problem have not yet been addressed in either academic papers or patents. Therefore, there is an urgent need for an in-situ testing device that can provide an economical, easy-to-operate, and highly accurate method for testing frozen soil thaw settlement under in-situ conditions to meet the needs of scientific research and practical applications in frozen soil engineering. Utility Model Content
[0006] To overcome the shortcomings of existing technologies, the technical problem to be solved by this utility model is to provide an in-situ test device for testing the thermal thaw settlement of frozen soil. The instrument realizes the thermal thaw settlement test of frozen soil by applying consolidation pressure and heat in the field through drilling, sampling, pressurization and heating. It has the advantages of simple structure, clear principle, low material consumption, low cost, easy assembly and strong adaptability. It avoids the problem of needing undisturbed samples for indoor and field tests, and improves the accuracy of data collection and the success rate of the test.
[0007] To achieve the aforementioned objective, this utility model provides an in-situ testing device for testing the thermal thaw settlement of frozen soil, comprising a steel pipe, a conversion joint connected to the top center of the steel pipe, and a drill rod connected to the top of the conversion joint; the upper part of the drill rod is connected to a drilling machine for driving the drill rod, conversion joint, and steel pipe to rotate and press down; a spiral and hollow copper tube is tightly attached to the inside of the steel pipe, and the inlet and outlet of the copper tube are respectively connected to a first thermostatic bath tube and a second thermostatic bath tube, which pass through the conversion joint and the inside of the drill rod in sequence and extend out of the drill rod; the first thermostatic bath tube is externally connected to an electric hot water tank heater placed on the ground, and the second thermostatic bath tube is externally connected to a water bucket placed on the ground; the lower part of the conversion joint is connected to a piston located in the steel pipe via a connecting rod, and the space between the bottom of the piston and the bottom of the steel pipe is a heating chamber, the interior of which is used to place a frozen soil sample; a reamer is threadedly connected to the bottom of the steel pipe, and a drill bit is connected to the bottom of the reamer, the cylindrical sample cut by the drill bit filling the heating chamber through the reamer.
[0008] Furthermore, the drill bit is a hollow cone-shaped body that is larger at the top and smaller at the bottom. The outer surface of the annular wall of the drill bit is welded with a first elongated cutting tool, a second elongated cutting tool, a third elongated cutting tool, and a fourth elongated cutting tool arranged at equal intervals. The bottom of the inner surface of the annular wall of the drill bit is welded with a first spherical cutting tool, a second spherical cutting tool, a third spherical cutting tool, a fourth spherical cutting tool, a fifth spherical cutting tool, a sixth spherical cutting tool, a seventh spherical cutting tool, and an eighth spherical cutting tool arranged at equal intervals.
[0009] Preferably, the outer circumferential surface of the steel pipe is decorated with a spiral pattern for soil removal.
[0010] Furthermore, the outer surface of the reamer is provided with a spiral cutterhead, which is used to remove the drilled waste soil to the ground during the drilling process.
[0011] Preferably, the outer circumferential surface of the connecting rod is provided with a first rubber ring and a second rubber ring arranged sequentially from top to bottom, which is used to keep the connecting rod at the center of the steel pipe, prevent the connecting rod and piston from being eccentric when pressurizing the frozen soil sample, and at the same time prevent heat loss from the heating chamber.
[0012] Preferably, a sealing ring is provided at 1 / 2 of the axial height of the piston to prevent direct friction between the piston and the steel pipe and to prevent heat loss from the heating chamber.
[0013] Furthermore, a ruler is vertically affixed to the surface of the drill rod.
[0014] Preferably, the drill bit, reamer, and heating chamber are coated with a 1mm thick layer of solid petroleum jelly.
[0015] Compared with the prior art, the in-situ test device for testing frozen soil thaw settlement of this utility model has at least the following beneficial effects and advantages:
[0016] 1. Simple structure and clear principle: Based on the field test principle of "Standard for Geotechnical Testing Methods GBT 50123-2019", the principle is simple and clear, making it easy for operators to understand and use;
[0017] 2. Low consumables and low cost: Instrument parts are common and easy to obtain, with low cost and mass production capability. The only consumable required for the experiment is circulating heated water, without generating additional consumables. The experiment has low cost and high repeatability.
[0018] 3. Easy to assemble and highly adaptable: The assembly steps are simple and there are few instrument parts. In practical applications, if heating for the sample is not provided, it can be used for frozen soil drilling and sampling. The instrument is highly adaptable and has multiple advantages.
[0019] 4. Capable of conducting in-situ thermal thawing tests: The instrument applies consolidation pressure and heat to conduct in-situ tests of frozen soil thermal thawing settlement.
[0020] 5. High success rate and high accuracy: Compared with indoor testing and large-volume field testing, the instrument conducts tests under in-situ conditions, which can avoid the influence of sample disturbance, resulting in a high success rate and high accuracy. Attached Figure Description
[0021] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is an overall structural diagram of the in-situ test device for testing the thermal thaw settlement of frozen soil according to this utility model.
[0023] Figure 2This is a schematic diagram of the contact state between the in-situ test device for testing frozen soil thermal thaw settlement of this utility model and the sample.
[0024] Figure 3 This is a schematic diagram of the steel pipe structure of this utility model;
[0025] Figure 4 This is a bottom view of the drill bit of this utility model.
[0026] Wherein: 1—Drill rod, 2—Scale, 3—Converter joint, 4a—First thermos tube, 4b—Second thermos tube, 5—Steel pipe, 6—Copper pipe, 7a—First rubber ring, 7b—Second rubber ring, 8—Connecting rod, 9—Piston, 10—Heating chamber, 11—Reamer, 12—Cutterhead, 13—Drill bit, 14—Frozen soil sample, 15a—First long strip cutter, 15b—Second long strip cutter, 15c—Third long strip cutter, 15d—Fourth long strip cutter, 16a—First spherical cutter, 16b—Second spherical cutter, 16c—Third spherical cutter, 16d—Fourth spherical cutter, 16e—Fifth spherical cutter, 16f—Sixth spherical cutter, 16g—Seventh spherical cutter, 16h—Eighth spherical cutter, 17—Spiral soil discharge pattern, 18—Sealing ring. Detailed Implementation
[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0028] See below Figures 1 to 4 This invention provides a detailed description of the in-situ test device for testing the thermal thaw settlement of frozen soil.
[0029] The in-situ testing device for testing frozen soil thaw settlement provided by this utility model includes a steel pipe 5, a drill rod 1, a conversion joint 3, a connecting rod 8, a piston 9, a reamer 11, and a drill bit 13. The conversion joint 3 is connected to the top center of the steel pipe 5, and the bottom of the drill rod 1 is connected to the conversion joint 3. The upper part of the drill rod 1 is connected to the ground turntable of a hydraulic geological exploration 200M drilling rig (manufactured by Shandong Wohai Heavy Industry Machinery Co., Ltd., with a drilling depth of 200m and a lifting capacity of 25kN). When the drilling rig is drilling, the ground turntable is hydraulically driven to rotate and press down, which in turn drives the drill rod 1, the conversion joint 3, and the steel pipe 5 to rotate and press down, thereby providing torque to the drilling tool and drilling for frozen soil samples 14. The diameter of the conversion joint 3 is twice the diameter of the drill rod 1, serving as a diameter reducer and reducing the torque on the drill rod 1 to prevent it from breaking.
[0030] The outer circumference of the steel pipe 5 is spiraled with a steel spiral soil-discharging pattern 17. Inside the steel pipe 5, a spiral-shaped, hollow copper pipe 6 is tightly fitted. The inlet and outlet of the copper pipe 6 are connected to the first thermostatic bath pipe 4a and the second thermostatic bath pipe 4b, respectively. The first thermostatic bath pipe 4a and the second thermostatic bath pipe 4b pass sequentially through the conversion joint 3 and the inside of the drill rod 1, and extend out of the drill rod 1. The first thermostatic bath pipe 4a is externally connected to an electric hot water tank heater (manufactured by Foshan Yaoyu Electromechanical Co., Ltd., model WT-1500, temperature accuracy ±1℃, power consumption 1500W) placed on the ground. The second thermostatic bath pipe 4b is externally connected to a water bucket (10L, commercially available) placed on the ground. During the thermal settling test, the water in the water tank is heated by the electric hot water tank heater. A water pump (commercially available) continuously pumps the hot water into the first thermostatic bath pipe 4a, the copper pipe 6, and the second thermostatic bath pipe 4b. The discharged wastewater flows into the water bucket. The flowing hot water provides the necessary thermal environment for the test around the underground frozen soil sample 14.
[0031] The upper part of the connecting rod 8 is connected to the lower part of the adapter 3 via threads. Its lower part passes through the first rubber ring 7a and the second rubber ring 7b in sequence, and then connects to the piston 9 via threads. A sealing ring 18 is fitted around the outer circumference of the piston 9. The space between the bottom of the piston 9 and the bottom of the steel pipe 5 is the heating chamber 10, which is used to place the frozen soil sample 14. The first rubber ring 7a and the second rubber ring 7b are arranged sequentially from top to bottom on the outer circumference of the connecting rod 8. Their function is to keep the connecting rod 8 centered on the steel pipe 5, preventing eccentricity when the connecting rod 8 and the piston 9 pressurize the frozen soil sample 14, and also preventing heat loss from the heating chamber 10. The sealing ring 18 is located at half the axial height of the piston 9. The sealing ring 18 is made of rubber, and its function is to prevent direct friction between the piston 9 and the steel pipe 5 when the piston 9 and the sealing ring 18 are pressed down, improving the service life of the piston 9, and also preventing heat loss from the heating chamber 10.
[0032] A reamer 11 is threadedly connected to the bottom of the steel pipe 5. Its function is to enlarge the borehole drilled by the conical drill bit 13. Simultaneously, the outer surface of the reamer 11 is equipped with a spiral cutterhead 12 to remove excavated soil to the surface during the drilling process, improving drilling efficiency. The bottom of the reamer 11 is connected to the drill bit 13, which is a hollow cone shape, wider at the top and narrower at the bottom. The outer surface of the annular wall of the drill bit 13 is welded with a first elongated cutter 15a, a second elongated cutter 15b, a third elongated cutter 15c, and a fourth elongated cutter 15d. The bottom of the inner surface of the annular wall of the drill bit 13 is welded with a first spherical cutter 16a, a second spherical cutter 16b, a third spherical cutter 16c, a fourth spherical cutter 16d, a fifth spherical cutter 16e, a sixth spherical cutter 16f, a seventh spherical cutter 16g, and an eighth spherical cutter 16h. The function of each long, narrow cutter is to cut the hard frozen soil blocks when drilling for frozen soil samples. Each spherical cutter can locally cut the frozen soil blocks, so that the frozen soil sample 14 is formed into a standard cylinder. When the drill bit 13 is drilling, when the frozen soil sample 14 fills the heating chamber 10, drilling stops, and the ground turntable is driven by the hydraulic system of the drilling rig to rotate in the opposite direction and lift 5 cm, so that the frozen soil sample 14 is completely separated from the underground soil, thus completing the sampling of the frozen soil sample.
[0033] A scale 2 is vertically affixed to the surface of drill rod 1. The scale 2 is made of waterproof low-density polyethylene with an accuracy of 1 mm. The function of scale 2 is to determine the drilling depth. The maximum drilling depth is the sum of the axial length of drill bit 13, reamer 11, steel pipe 5 and adapter 3 and the advance length shown on scale 2.
[0034] The center lines of drill pipe 1, drill changer 3, connecting rod 8, first rubber ring 7a, second rubber ring 7b, and piston 9 must be aligned with the vertical center line of the long cylindrical steel pipe 5. The gap between the first rubber ring 7a, second rubber ring 7b, sealing ring 18, and copper pipe 6 is 0.1mm.
[0035] The steel pipe 5 is 120cm long, with an outer diameter of 76mm and an inner diameter of 70mm. The copper pipe 6 is a hollow cylindrical tube with an outer diameter of 10mm and an inner diameter of 8mm. The reamer 11 is a hollow cylindrical tube with an outer diameter of 76mm and an inner diameter of 50mm. The space formed by the coiled copper pipe 6 has an inner diameter of 50mm (i.e., the inner diameter of the steel pipe 5 minus the diameters of two copper pipes), ensuring that the drilled frozen soil sample is a standard cylinder with a diameter of 50mm.
[0036] Drill bit 13 is made of diamond, with an upper outer wall diameter of 76 mm and a lower outer wall diameter of 70 mm. The diameter of the hollow cylinder inside drill bit 13 is 50 mm. The first elongated cutting tool 15a, the second elongated cutting tool 15b, the third elongated cutting tool 15c, and the fourth elongated cutting tool 15d are arranged at equal intervals, i.e., at a 90-degree angle. The first spherical cutting tool 16a, the second spherical cutting tool 16b, the third spherical cutting tool 16c, the fourth spherical cutting tool 16d, the fifth spherical cutting tool 16e, the sixth spherical cutting tool 16f, the seventh spherical cutting tool 16g, and the eighth spherical cutting tool 16h are arranged at equal intervals, i.e., at a 45-degree angle.
[0037] Before testing the drill bit 13, the reamer 11 and the heating chamber 10, a 1mm thick layer of solid petroleum jelly needs to be applied.
[0038] Below, refer to Figures 1 to 4 Based on the above description of structural features, the working principle of the in-situ test device for testing frozen soil thaw settlement of this utility model is briefly described as follows:
[0039] The hydraulic drilling rig provides torque and downward pressure to drill for samples and provide consolidation pressure for the frozen soil sample 14. The entire device of this invention is drilled into the ground through the drill bit 13 and the reamer 11. Waste soil is discharged upward to the ground through the spiral soil discharge pattern 17 and the spiral cutter head 12. The drilled frozen soil sample 14 passes through the hollow drill bit 13 and the reamer 11 and is pressed into the heating chamber 10. The ground turntable is driven by the hydraulic system of the drilling rig to rotate in the opposite direction and lift up, so that the bottom of the frozen soil sample 14 is broken off, thus achieving the purpose of drilling the frozen soil sample 14.
[0040] Then, the connection between the drill rig, drill rod 1, and adapter 3 is disassembled. The connecting rod 8 is extended to the ground via a threaded connection. The drill rig is used to press down on the connecting rod 8 and piston 9 to provide vertical consolidation pressure to the frozen soil sample 14. The consolidation pressure is the downward pressure divided by the cross-sectional area of the sample. At the same time, flowing water is heated on the ground using an electric hot water heater. The heated water is circulated into the copper pipe 6 around the frozen soil sample 14 through the first thermotubule 4a and flows out through the second thermotubule 4b. By increasing the temperature around the sample, the frozen soil sample 14 melts and undergoes settlement deformation. According to the requirements of the "Standard for Geotechnical Testing Methods GBT 50123-2019", the test takes 24 hours. After the test, the connecting rod 8 is lifted. Since the diameter of the piston 9 is larger than the diameter of the conversion joint 3, the entire device can be lifted out of the ground. The drill bit 13, the reamer 11, the connecting rod 8, the first rubber ring 7a, the second rubber ring 7b, the piston 9, and the sealing ring 18 are removed in sequence. The frozen soil sample 14 at the connection between the steel pipe 5 and the reamer 11 is cut with a soil cutter (commonly available). The frozen soil sample 14 in the heating chamber 10 is pushed out with a bulldozer (commonly available). The axial height H1 of the pushed-out frozen soil sample 14 is measured with a micrometer. Since Vaseline was applied before the test, the bulldozing process will not disturb the frozen soil sample 14. The initial axial length H0 of the frozen soil sample is the difference between the axial length of the steel pipe 5 and the axial length of the piston 9 and the connecting rod 8 inside the steel pipe 5. Therefore, the thermal thaw settlement Hi = H0 - H1, in mm. This achieves a frozen soil thermal thaw settlement test under in-situ conditions, simultaneously applying consolidation pressure and heat.
[0041] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any transformations or substitutions that can be understood by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of this utility model.
Claims
1. An in-situ test apparatus for testing thaw settlement of frozen ground, characterized by, The device comprises a steel pipe (5), a transition joint (3) connected at the top center of the steel pipe (5), a drill pipe (1) connected with the top of the transition joint (3); the upper part of the drill pipe (1) is connected with a drilling machine for driving the rotation and downward pressure of the drill pipe (1), the transition joint (3) and the steel pipe (5). The inside of the steel pipe (5) is tightly attached with a spiral and hollow copper pipe (6), the inlet and outlet of the copper pipe (6) are connected with a first warm bath pipe (4a) and a second warm bath pipe (4b) respectively, the first warm bath pipe (4a) and the second warm bath pipe (4b) pass through the inside of the transition joint (3) and the drill pipe (1) in turn and extend out of the drill pipe (1); the first warm bath pipe (4a) is externally connected with an electric water heater placed on the ground, and the second warm bath pipe (4b) is externally connected with a bucket placed on the ground. The lower part of the transition joint (3) is connected with a piston (9) located in the steel pipe (5) through a connecting rod (8), the space between the bottom of the piston (9) and the bottom of the steel pipe (5) is a heating cavity (10), and the inside of the heating cavity (10) is used for placing a frozen soil sample (14). The bottom of the steel pipe (5) is connected with a reamer (11) through a thread, the bottom of the reamer (11) is connected with a drill bit (13), and the cylindrical sample cut by the drill bit (13) fills the heating cavity (10) through the reamer (11).
2. The in-situ test apparatus for testing the thaw settlement of frozen ground according to claim 1, characterized by, The drill bit (13) is a hollow conical body with a large upper part and a small lower part, and the outer surface of the ring wall of the drill bit (13) is welded with first, second, third and fourth long strip-shaped cutters (15a, 15b, 15c, 15d) arranged at equal intervals. The inner surface of the ring wall of the drill bit (13) is welded with first, second, third, fourth, fifth, sixth, seventh and eighth spherical cutters (16a, 16b, 16c, 16d, 16e, 16f, 16g, 16h) arranged at equal intervals.
3. The in-situ test apparatus for testing the thaw settlement of frozen ground according to claim 1, characterized by, The outer circumferential surface of the steel pipe (5) is spirally provided with a steel spiral soil removal pattern (17).
4. The in-situ test apparatus for testing the thaw settlement of frozen ground according to claim 1, characterized by, The outer surface of the reamer (11) is provided with a spiral cutter head (12) for removing the waste soil drilled during the drilling process to the ground.
5. The in-situ test apparatus for testing thaw settlement of frozen ground according to claim 1, characterized by, The outer circumferential surface of the connecting rod (8) is provided with a first rubber ring (7a) and a second rubber ring (7b) arranged in turn from top to bottom, so that the connecting rod (8) is located at the center of the steel pipe (5), preventing the connecting rod (8) and the piston (9) from being eccentric when pressing the frozen soil sample (14), and preventing heat loss of the heating cavity (10).
6. The in-situ test apparatus for testing thaw settlement of frozen ground according to claim 1, characterized by, The sealing ring (18) is arranged at 1 / 2 of the axial height of the piston (9) to avoid direct friction between the piston (9) and the steel pipe (5) and prevent heat loss of the heating cavity (10).
7. The in-situ test apparatus for testing thaw settlement of frozen ground according to claim 1, characterized by, The surface of the drill pipe (1) is vertically attached with a scale (2).
8. The in-situ test apparatus for testing thaw settlement of frozen ground according to claim 1, wherein, The inside of the drill bit (13), the reamer (11) and the heating cavity (10) are coated with solid vaseline with a thickness of 1 mm.