Method for assisting in rapid detection of compactness of backfill soil
A plumb bob and electric motor-based device rapidly assesses soil compaction by counting hammer strikes, addressing the inefficiencies of existing methods and enhancing construction speed and cost-effectiveness.
Patent Information
- Application Number
- CN202411344956.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-27
AI Technical Summary
Existing methods for measuring soil compaction in roadbed earthwork are either time-consuming, require expensive equipment, or pose radiation hazards, making them unsuitable for large-scale or rapid assessments.
A device that uses a plumb bob and electric motor to hammer the soil and count hammer strikes per unit depth, comparing these to benchmark values for density qualification.
The method is fast, easy to operate, and cost-effective, allowing real-time adjustments for soil quality, thus improving construction efficiency.
Smart Images
Figure CN119195099A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of construction engineering, and in particular provides a method for quickly detecting the density of auxiliary backfill soil. The method is suitable for soils with finer particles and more evenly distributed particles, such as sand, clay, loess, and silty clay, but is not suitable for pebbles and graded soils. Background Art
[0002] The background of density testing during the backfilling of roadbed earthwork is to ensure the quality and safety of earthwork backfilling, so as to ensure that the technical indicators such as the flatness and bearing capacity of the road meet or exceed the specified requirements. The earthwork density index is usually measured by the compaction coefficient or dry density index, also known as compaction degree, loose density, etc.
[0003] Commonly used methods for testing the compaction of roadbed soil include in-situ density measurement, nuclear density meter and static pressure load test, etc. However, these testing methods have their own advantages and disadvantages.
[0004] 1. The existing in-situ density measurement method is to set measurement points on the surface of the earthwork and measure the density without destroying the soil. This method is simple to operate and does not affect the stability of the soil layer, but it requires the use of professional instruments and equipment for secondary processing, which takes a long time to produce test data and affects the construction period.
[0005] 2. Nuclear density meter is a high-tech measurement method that uses the principle of nuclear radiation effect to measure soil density. It is simple, fast, high-precision, and does not require leading burial pits. It has fast detection speed, accurate data, easy operation, and will not affect the soil. However, the equipment has certain radiation hazards and the equipment itself is expensive.
[0006] 3. Static pressure load test is a more rigorous method for measuring compaction. When measuring and calculating, it will be corrected according to Poisson's ratio. Its advantages are high measurement accuracy and wide application range. It can measure compaction values at different depths and under different penetration conditions. However, the test takes a long time and is relatively expensive, so it is not suitable for large-scale ground compaction measurements.
[0007] In summary, different compaction detection methods have their own advantages and disadvantages, which need to be comprehensively considered in light of the actual situation, and the appropriate detection method should be flexibly selected according to the needs of the project at different stages. Summary of the invention
[0008] The purpose of the present invention is to provide a method for quickly detecting the compactness of auxiliary backfill soil, which is mainly used in the fields of municipal and earthwork engineering construction.
[0009] The present invention comprises the following steps:
[0010] Step 1: Determine baseline data
[0011] During the backfill construction, first, the device is used to randomly collect n points as benchmark data in the area with the same soil quality that has been backfilled and compacted (for the convenience of calculation, n is greater than 10 and is an integer multiple of 10). When collecting benchmark data, the device is placed in the area to be collected, the power switch 9 is turned on, and the electric motor 3 drives the rotating pressure rod 5 to press the tail of the plumb bob 2 to raise the front end of the plumb bob to a fixed height. The plumb bob 2 falls by its own gravity and hammers the detection rod 7 below to make it hit the soil layer to be collected. The electric motor 3 rotates in a cycle to drive the plumb bob 2 to hammer continuously. At the same time, the staff synchronously records the number of hammering times per unit depth of the detection rod 7 into the soil layer. After all the points to be collected are collected, all data are weighted averaged to determine the benchmark value.
[0012] Step 2: Backfill soil density test
[0013] (1) After the reference value is determined, when testing the density of the backfill soil, the detection device is manually lifted to the location to be tested through the handle 10 on the protective housing 12.
[0014] (2) The device body is rotated to the working position through the limit rod 11. During the rotation, the detection rod 7 is slightly lifted to make it off the ground to prevent the detection rod 7 from being inserted into the ground and unable to rotate to the specified position.
[0015] (3) Start the power switch 9, and drive the rotating pressure rod 5 through the electric motor 3 to press the tail of the plumb bob 2 so that the front end of the plumb bob rises to a fixed height. The plumb bob 2 falls due to its own gravity and hits the detection rod 7 below so that it hits the soil layer to be collected.
[0016] (4) The electric motor 3 rotates cyclically to drive the plumb bob 2 to hammer continuously. At the same time, the staff synchronously records the number of hammering times of the probe rod 7 per unit depth into the soil layer.
[0017] Step 3: Determine the results
[0018] After the test points are collected, the density of the monitored area is determined by comparing the number of hammer strikes per unit depth of the soil layer with the benchmark value. If the number of hammer strikes per unit depth of the soil layer is greater than or equal to the benchmark value, the backfill density is qualified; if the number of hammer strikes per unit depth of the soil layer is less than the benchmark value, the backfill density is unqualified.
[0019] The backfill soil density monitoring device includes: a plumb bob bracket 1; a plumb bob 2; an electric motor 3; a speed change gear set 4; a pressure rod 5; a battery pack 6; a detection rod 7; an electronic counter 8; a power switch 9; a handle 10; a limit rod 11; a protective shell 12; a device main body platform 13; and a central axis 14.
[0020] When in use, the main platform 13 can move freely up and down along the central axis 14. At the same time, the surface of the central axis 14 and the detection rod 7 are marked with scales to facilitate the measurement personnel to record the detection depth at any time.
[0021] The device body is integrally supported on the detection rod fixing block below through the support rod below. During detection, the device body platform 13 falls synchronously with the downward movement of the detection rod 7.
[0022] Before testing, check whether all aspects of the equipment are normal. After confirming that everything is normal, turn on the power switch. The electric motor 3 drives the rotating pressure rod 5 to press the tail of the plumb bob 2 to raise the front end of the plumb bob 2 to a fixed height. The plumb bob 2 falls by its own gravity and hammers the detection rod 7 below to make it hit the soil layer to be tested. The motor 3 rotates in a cycle to drive the plumb bob to hammer continuously. When the detection rod 7 reaches a fixed depth, the electric motor 3 stops operating (it can also be stopped with manual assistance). Finally, the number of hammering per unit depth into the soil layer is compared with the benchmark value to determine whether the density of the monitored area is qualified.
[0023] The advantages of the present invention are that it is easy to operate, simple and practical, saves a lot of test time, and can be adjusted at any time according to the construction location and soil quality. It is convenient and fast, and greatly improves the construction progress. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Schematic diagram of the probe rod and plumb bob.
[0025] Figure 2 Schematic diagram of the main components.
[0026] Figure 3 This is an oblique view of the internal structure without the protective shell installed.
[0027] Figure 4 An oblique view of the quick monitoring device after installing the protective casing.
[0028] Figure 5 This is a 3D rendering.
[0029] In the figure, there are a plumb bob bracket 1, a plumb bob 2, an electric motor 3, a speed change gear set 4, a pressure rod 5, a battery pack 6, a detection rod 7, an electronic counter 8, a power switch 9, a handle 10, a limit rod 11, a protective casing 12, a device main body platform 13, and a central axis 14. DETAILED DESCRIPTION
[0030] Figure 1-Figure 4 This is a specific implementation of the present invention. The specific implementation steps are as follows:
[0031] Acquisition of benchmark data → Calculation and recording of benchmark data → Testing of the area to be tested → Result evaluation
[0032] The present invention is further described below in conjunction with the accompanying drawings.
[0033] 1. Before using this device to monitor the density of earth backfill construction, first use this device to randomly collect n points (for the convenience of calculation and to ensure the accuracy of the data, n is greater than 10 and is a multiple of 10) in the area where the same soil has been compacted as the benchmark data. After placing the device in the area to be collected, start the power switch 9, and drive the rotating pressure rod 5 through the electric motor 3 to press the tail of the plumb bob 2 to raise the front end of the plumb bob to a fixed height. The plumb bob 2 falls by its own gravity and hammers the detection rod 7 below to make it hit the soil layer to be collected. The electric motor 3 rotates in a cycle to drive the plumb bob 2 to hammer continuously. At the same time, the staff synchronously records the number of hammering times per unit depth of the detection rod 7 into the soil layer. After all the points to be collected are collected, all data are weighted averaged to determine the benchmark value.
[0034] 2. When testing, manually lift the handle and place it on the location to be tested. Rotate the device body to the working position through the limit rod 11. When rotating, slightly lift the detection rod 7 to prevent it from being inserted into the ground and unable to rotate to the specified position.
[0035] 3. The main platform can move freely up and down along the central axis. At the same time, there are scales on the surface of the central axis and the detection rod, which is convenient for measurement personnel to record the detection depth.
[0036] 4. The main body of the device is supported by the support rod below on the fixed block of the detection rod below. When testing, the main platform of the device will fall synchronously with the downward movement of the detection rod.
[0037] 5. Before conducting the density test, it is necessary to check whether all aspects of the equipment are operating normally, and turn on the power switch after confirming that everything is correct. The electric motor 3 will drive the rotating pressure rod to press the tail of the plumb bob, so that the front end of the plumb bob 2 rises to a fixed height. Then, the plumb bob 2 falls by its own gravity and continuously hammers the detection rod 7 below, so that it hits the soil layer to be tested. The electric motor 3 will operate in a cycle, continuously driving the plumb bob 2 to hammer.
[0038] 6. When the rod 7 to be detected reaches the set depth, the electric motor 3 will stop operating (it can also be stopped manually).
[0039] 7. Finally, the number of hammer blows per unit depth is counted and compared with the benchmark value to determine whether the density of the monitored area is qualified. If the number of hammer blows per unit depth of the soil layer is greater than or equal to the benchmark value, the backfill density is qualified; if the number of hammer blows per unit depth of the soil layer is less than the benchmark value, the backfill density is unqualified.
[0040] The implementation principle of the method for rapid detection of backfill soil density in an embodiment of the present application is as follows: when detecting the backfill soil density, the number of hammer strikes of the detection rod 7 with the same hammer force and the same frequency within a unit depth of the soil layer is compared with the benchmark value, so as to determine whether the friction coefficient, resistance value, bearing capacity, etc. of the backfill soil layer are greater than or equal to the qualified area to determine whether the density of the monitored area is qualified.
Claims
1. A method for rapid detection of backfill soil density, characterized in that: The steps include: Step 1: Determine baseline data During the backfill construction, the device first randomly collects n points in the area with the same soil quality that has been backfilled and compacted as the benchmark data. When collecting benchmark data, the device is placed in the area to be collected, the power switch (9) is turned on, and the electric motor (3) drives the rotating pressure rod (5) to press the tail of the plumb bob (2) to make the front end of the plumb bob rise to a fixed height. The plumb bob (2) falls by its own gravity and hammers the detection rod (7) below so that it hits the soil layer to be collected; the electric motor (3) rotates cyclically to drive the plumb bob (2) to hammer continuously, and the staff simultaneously records the number of hammering times per unit depth of the detection rod (7) into the soil layer; After all the data points to be collected are collected, all data are weighted averaged to determine the benchmark value; Step 2: Backfill soil density test When testing the density of backfill soil, The inspector lifts the inspection device to the location to be inspected by using the handle on the protective housing (12); The device body is rotated to a working position through a limiting rod (11), and the detection rod (7) is slightly lifted to separate it from the ground during the rotation to prevent the detection rod (7) from being inserted into the ground and unable to rotate to a specified position; The power switch (9) is turned on, and the electric motor (3) drives the rotating pressure rod (5) to press the tail of the plumb bob (2) so that the front end of the plumb bob rises to a fixed height. The plumb bob (2) falls by its own gravity and hits the detection rod (7) below so that it hits the soil layer to be collected; The electric motor (3) rotates cyclically to drive the plumb bob (2) to hammer continuously, and the staff simultaneously records the number of hammerings per unit depth of the probe rod (7) into the soil layer; Step 3: Determine the results After the collection of test points is completed, the number of hammer blows per unit depth into the soil layer is compared with the benchmark value to determine whether the density of the monitored area is qualified. If the number of hammer blows per unit depth into the soil layer is greater than or equal to the benchmark value, the backfill density is qualified; if the number of hammer blows per unit depth into the soil layer is less than the benchmark value, the backfill density is unqualified.
2. The method for rapid detection of compactness of auxiliary backfill soil according to claim 1, characterized in that: The backfill soil density monitoring device comprises: a plumb bob bracket (1); a plumb bob (2); an electric motor (3); a speed-changing gear set (4); a pressure rod (5); a battery pack (6); a detection rod (7); an electronic counter (8); a power switch (9); a handle (10); a limit rod (11); a protective shell (12); a device main body platform (13); and a central axis (14).
3. The method for rapid detection of the density of auxiliary backfill soil according to claim 1, characterized in that: Before testing, check whether all aspects of the equipment are normal. After confirming that they are normal, start the power switch. The electric motor (3) drives the rotating pressure rod (5) to press the tail of the plumb bob (2) to make the front end of the plumb bob (2) rise to a fixed height. The plumb bob (2) falls by its own gravity and hammers the detection rod (7) below so that it hits the soil layer to be tested. The motor (3) rotates cyclically to drive the plumb bob to hammer continuously. When the detection rod (7) reaches a fixed depth, the electric motor (3) stops operating. Finally, by comparing the number of hammering per unit depth of the soil layer with the benchmark value, it is determined whether the density of the monitored area is qualified.