A device and method for quantitatively testing the pulverization of roadbed fill

Abstract

The present application relates to the technical field of subgrade filler selection and testing, and particularly relates to a subgrade filler pulverization quantitative testing device and a testing method. The device comprises a ring track, a driving motor, a soil pressure cell, a pressure testing groove, a pulverization rate testing groove, a rubber wheel, a connecting rod and a counterweight box. The pulverization rate testing groove and the pressure testing groove are respectively located on the two symmetrical sides in the ring track, the pulverization rate testing groove is used for filling the filler, and the soil pressure cell is arranged in the pressure testing groove. The driving motor is arranged at the center position of the ring track, the rubber wheel is connected with the output shaft of the driving motor through the connecting rod, the rubber wheel can uniformly roll in the ring track, and the rubber wheel can roll and rub the filler in the pulverization rate testing groove. The rubber wheel is provided with the counterweight box, the counterweight box can load the counterweight block to realize different wheel pressures, the pulverization rate of the filler with different blending ratios under different rolling times and different rolling pressures is determined, the pulverization degree of the soil is judged, and the basis for the optimization of the filler blending ratio can be provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of subgrade filler selection and testing, and particularly relates to a subgrade filler pulverization quantitative testing device and method. BACKGROUND

[0002] Full-weathered phyllite is widely distributed in the northern part of Jiangxi Province. The weathered phyllite is rapidly converted into fine particles under the action of a road roller due to its low hardness and high weathering degree, and is therefore referred to as phyllite soil. The phyllite soil contains a large amount of silt particles. Due to the low cohesion of the phyllite soil and the lack of hardening, the subgrade compaction is poor. Under the combined action of sunlight and heavy trucks, the phyllite soil is easily pulverized. When a transport filler self-unloading vehicle travels on the phyllite soil, a loose soil layer is often formed. The loose soil layer is difficult to compact and clean, and forms a loose soil interlayer in the layered compaction, which causes serious quality problems of the subgrade. At the same time, the pulverized loose soil layer easily causes dust, which causes the on-site PM2.5 to be much higher than the normal level, causing harm to the health of construction workers and a significant impact on the environment, and causing the environmental department to strictly control the construction site.

[0003] Fine-grained soil, especially silt soil, is easily pulverized and forms a loose interlayer, which also causes dust during construction, causing a significant impact on the construction unit. However, silt soil can be improved by adding red clay or cement, thereby reducing the harm caused by the pulverization of fine-grained soil. However, there is currently no testing device for quantitatively measuring the pulverization rate of fine-grained soil. When field tests are used, a subgrade test section needs to be established, which is not suitable for controlling temperature conditions and rolling conditions, is relatively expensive, and is not suitable for quantitative measurement and comparison of the pulverization rate of various improvement schemes. Therefore, there is an urgent need in the engineering field for a device and method for quantitatively measuring the pulverization rate of fine-grained soil. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a subgrade filler pulverization quantitative testing device and method, which can quantitatively evaluate the pulverization rate of fine-grained soil and quickly evaluate the pulverization rate of fillers with different proportions under the same conditions.

[0005] To achieve the above object, the present application is realized by the following technical solutions.

[0006] The application provides a roadbed filler pulverization quantitative testing device, which comprises a ring track, a driving motor, a soil pressure box, a pressure testing groove, a pulverization rate testing groove, a rubber wheel, a connecting rod, a counterweight box, counterweight blocks and a heating device; the pressure testing groove and the pulverization rate testing groove are fan-shaped grooves and are located on the two symmetrical sides in the ring track respectively, the pulverization rate testing groove is used for filling the filler, and the soil pressure box is arranged in the pressure testing groove; the driving motor is arranged at the center position of the ring track, the center bearing of the rubber wheel is connected with the connecting rod, the connecting rod is connected with the output shaft of the driving motor, the rubber wheel can uniformly roll in the ring track and roll and rub the filler in the pulverization rate testing groove, the counterweight box is arranged on the rubber wheel, the counterweight blocks are arranged in the counterweight box, and the heating device uses a warm air blower; the heating device is fixed on the side of the pulverization rate testing groove through a movable support and is used for heating the filler in the pulverization rate testing groove, and a temperature measuring gun can be used to measure the heating temperature of the filler.

[0007] Further, the outer diameter of the ring track is 45 cm, the inner diameter is 30 cm, and the width is 15 cm, a ring rolling groove is formed, the rubber wheel can uniformly roll in the ring track, and the filler in the pulverization rate testing groove is rolled and rubbed.

[0008] Further, the pulverization rate testing groove is welded by 10 mm iron plates, the outer diameter is 45 cm, the inner diameter is 30 cm, the width is 15 cm, and the corresponding central angle is 30°. The pulverization rate testing groove is mainly used for testing the pulverization rate of fine soil, the width of 15 cm is three times the width of the rubber wheel, and when the pressure of the rubber wheel on the filler surface exceeds the bearing capacity of the filler surface, the filler can be squeezed out from the two sides of the rubber wheel.

[0009] Further, the pressure testing groove is opposite to the pulverization rate testing groove, the outer diameter is 45 cm, the inner diameter is 30 cm, the width is 15 cm, and the corresponding central angle is 15°. A soil pressure box with a diameter of 5 cm is arranged at the center of the pressure testing groove, the filler with the same water content and the same compactness as those in the pulverization rate testing groove is filled around the soil pressure box, the embedding depth of the soil pressure box is 1 cm, and the soil pressure testing range is 50-1000 kPa.

[0010] Further, the driving motor is a low-speed motor, and a Songgang constant-speed optical shaft low-speed motor is adopted, the motor has a fixed rotating speed of 15 revolutions per minute, a maximum power of 200W, and adopts a 220V power supply, the driving motor is connected with the center bearing of the rubber wheel through a connecting device and a connecting rod, and can drive the rubber wheel to roll in the annular track, and the driving motor is fixed on the center of the device (i.e. the center of the annular track) through a support, so that the rubber wheel can roll in the middle position of the rolling groove.

[0011] Further, the rubber wheel has a hub in the middle, the hub is connected with the center bearing through spokes, and the center bearing is connected with the driving motor through the connecting rod, and the hub is surrounded by a rubber tire, and the rubber tire is provided with transverse patterns and two longitudinal patterns to simulate the rolling and friction of the automobile tire on the filler.

[0012] Further, the connecting rod is welded with a counterweight box, the counterweight box is located above the rubber wheel, and the counterweight box is provided with counterweight blocks, and the pressure of the rubber wheel on the filler surface in the pulverization rate test groove and the pressure test groove can be increased or decreased by adding or reducing the counterweight blocks.

[0013] Further, the roadbed filler pulverization quantitative test device is also provided with a data acquisition instrument, the data acquisition instrument is electrically connected with the earth pressure cell through a data line, and is used for collecting the pressure data of the filler surface.

[0014] On the other hand, the application also provides a roadbed filler pulverization quantitative determination method, and the specific steps are as follows: filling the filler with a specific ratio, a specific water content and a specific compactness in the pulverization rate test groove and the pressure test groove, heating the filler in the pulverization rate test groove by using a warm air blower, starting the driving motor when the temperature reaches 50 DEG C, driving the rubber wheel to make a circular motion in the annular track, and rolling and rubbing the filler in the pulverization rate test groove; at this time, the earth pressure is determined by the earth pressure cell and the data acquisition instrument, when the earth pressure is not suitable, the motor is immediately stopped, the pressure of the rubber wheel on the filler surface is changed by changing the size or quantity of the counterweight blocks, when the measured earth pressure meets the requirements, the formal test is started, and the rolling number of the front rubber wheel is counted as the rolling number of times; after a specific rolling number of times (for example, 100 times, 200 times), the loose soil formed in the pulverization rate test groove is collected, and the weight of the dried loose soil is measured, and the pulverization rate of the fine-grained soil is quantitatively evaluated by the ratio of the weight of the dried loose soil to the dry weight of the filler in the test groove. The optimal ratio is determined by comparing the pulverization rates of different ratio fillers with the same rolling number of times.

[0015] The application has the following beneficial effects:

[0016] (1) The test device is miniaturized, the workload of the field test section is reduced, and the test cost is saved.

[0017] The conventional quantitative evaluation of the pulverization rate of the fine-grained soil must be determined by a field test section, and the test time is long and the cost is high, and by using the device and method, the pulverization quantitative evaluation of the fillers with different proportions can be obtained without using the field test section, thereby providing a basis for selecting the fillers, and a large amount of test time and field test cost is saved.

[0018] (2) The amount of the test filler is reduced, and the selection of the fillers with various proportions is facilitated.

[0019] The conventional test section needs a large amount of fillers (about 106 tons of fillers are needed for a 50m test section of a single line test section) to carry out the test, and if N kinds of proportions are needed, N*106 tons of fillers are needed to complete the test, and a large amount of fillers and large construction machinery are needed. After the application, a small amount of fillers (about 18 kg) is needed for each proportion to complete the pulverization quantitative evaluation, and therefore the test cost is saved, the selection of a large amount of filler proportions is facilitated, and the application is particularly suitable for the pulverization measurement of phyllite soil and red clay mixture.

[0020] (3) The test conditions are facilitated to be controlled

[0021] The pulverization of the fine-grained soil is generally tested under the conditions of solar heating, a certain pressure, a certain compaction degree and a certain water content. The test conditions are not convenient to control in the conventional test section, for example, the temperature of the fillers is required to be substantially the same in the test of the pulverization of the fine-grained soil under the condition of solar heating, which is difficult to control in the field test, and the heating condition and the water content cannot be controlled when it rains. In addition, the pressure of the roadbed surface by the transport vehicle is required to be substantially the same in the pulverization test, but the pressure of the roadbed surface by the tire is controlled by the amount of the fillers loaded on the vehicle, and therefore the pressure changes greatly. After the application, the temperature of the fillers can be controlled by the heating time of the warm air blower, the test can be free from the influence of rain in the indoor test. The pressure of the fillers by the rubber wheel is controlled by the weight of the counterweight, and the rolling times are controlled by the number of revolutions of the rubber wheel around the rolling groove, and the variables can be more accurately controlled.

[0022] (4) The pulverization rate is facilitated to be quantitatively determined

[0023] The pulverization rate of the fine-grained soil in the roadbed test section needs to collect the fine-grained soil pulverized in a long distance roadbed (for example, a 5m area in a 100m test section), the roadbed surface is wide, the friction of the road section by the vehicle is uneven, the amount is large and difficult to collect, and the soil needs to be dried for a long time before being determined. After the application, only a small amount of pulverized soil in the test groove needs to be collected, and the pulverization rate can be obtained by weighing the dried pulverized soil, and the optimal proportion can be selected by comparing the pulverization rates of the fillers with different proportions. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0025] Figure 1 The front view of the main structure of the subgrade filler pulverization quantitative testing device.

[0026] Figure 2 The top view of the rolling groove, the pulverization rate testing groove and the pressure testing groove.

[0027] Figure 3 The structural schematic diagram of the rubber wheel and the counterweight box and the counterweight block.

[0028] The figure mark explanation: 1-ring track, 2-soil pressure cell, 3-data acquisition instrument, 4-pressure testing groove, 5-rolling groove, 6-rubber wheel, 7-driving motor, 8-connecting rod, 9-rolling track, 10-counterweight block, 11-counterweight box, 12-pulverization rate testing groove, 13-spoke, 14-warm air blower, 15-temperature measuring gun. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the above-mentioned purposes, features and advantages of the present application, the following will further describe the present application in combination with the drawings and specific embodiments. In the following description, a lot of specific details are set forth in order to fully understand the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the present application is not limited to the specific embodiments disclosed below.

[0030] Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the general meanings understood by those skilled in the art. The terms "first", "second" and similar terms used in the patent application specification and claims do not represent any order, number or importance, but are only used to distinguish different components. Similarly, "one" or "a" and similar terms do not represent a number limit, but represent the existence of at least one. The terms "connected" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationships, when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0031] As Figures 1-3The device is shown as one kind of subgrade fine particle filling pulverization quantitative test device, the combined device belongs to the technical field of subgrade test equipment, mainly by annular track 1, earth pressure cell 2, data acquisition instrument 3, pressure test groove 4, low-speed drive motor 7, rubber wheel 6, pulverization rate test groove 12, counterweight box 11 and heating equipment are connected.The pulverization rate test groove 12 and the pressure test groove 4 are fan-shaped grooves, which are located on both sides of the annular track 1, the pulverization rate test groove 12 is used for filling filling material, the earth pressure cell 2 is arranged in the pressure test groove 4, and the earth pressure cell 2 is electrically connected with the data acquisition instrument 3 through a data line, for collecting pressure data on the surface of the filling material;The driving motor 7 is arranged at the center position of the annular track 1, the center bearing of the rubber wheel 6 is connected with the connecting rod 8, the connecting rod 8 is connected with the output shaft of the driving motor 7, and the rubber wheel 6 can uniformly roll in the annular track 1, and the filling material in the pulverization rate test groove 12 is rolled and rubbed;The rubber wheel 6 is provided with the counterweight box 11, and the counterweight box 11 is provided with the counterweight 10;The heating equipment includes a hair dryer 14 and a temperature measuring gun 15, which is used for heating the filling material in the pulverization rate test groove to 50 DEG C, and the hair dryer is used for heating the pulverization rate test groove, and the heating of the sun on the subgrade filling material in the rolling process can be simulated, so that the test environment is close to the actual situation.

[0032] In the embodiment, the low-speed driving motor 7 adopts a Songgang constant-speed optical shaft low-speed motor, the motor fixed speed is 15 revolutions per minute, the rated power is 200W, a 220V power supply is adopted, and the motor is connected with the center bearing of the rubber wheel 6 through a switching device and a connecting rod 8.The motor drives the rubber wheel to rotate around the center, and makes the rubber wheel uniformly roll in the rolling groove.The driving motor is fixed on the center of the equipment through a support, so that the rubber wheel can roll in the middle position of the rolling groove.

[0033] As shown in Figure 1 , the annular track can make the simulated automobile rubber wheel uniformly roll in the rolling groove, and roll and rub the filling material in the test groove, so that the fine soil is pulverized.As shown in Figure 2 , the outer diameter D of the annular track is 45cm, the inner diameter d is 30cm, and the width is 15cm, forming a circumferential rolling groove 5, which can make the rubber wheel 6 roll in the rolling groove 5, and roll and rub the filling material in the pressure test groove 4 and the pulverization rate test groove 12, and the rolling track 9 of the rubber wheel 6 is shown by the dotted line in Figure 2 . In addition to the pulverization rate test groove and the pressure test groove in the annular track, the bottom surface of the annular groove is flush with the top surface of the filling material in the pulverization rate test groove and the pressure test groove, that is, the rubber wheel rolls in a plane.

[0034] The ring track 1 is arranged with a pulverization rate test groove 12 on one side, which is welded by 10mm iron plate, with an outer diameter of 45cm, an inner diameter of 30cm, a width of 15cm, a depth of 15cm, and a corresponding central angle of 30°. The pulverization rate test groove 12 is mainly used for testing the pulverization rate of fine soil, and the width of 15cm is three times of the rubber wheel, so that the filler can be squeezed out on both sides of the rubber wheel when the pressure of the rubber wheel on the filler surface exceeds the bearing capacity of the filler surface. When the filler is filled, it can be compacted in three layers, and the compaction degree is controlled by calculating the soil quantity and the corresponding thickness.

[0035] The ring track 1 is arranged with a pressure test groove 4 on the other side, which is welded by 10mm iron plate, with an outer diameter of 45cm, an inner diameter of 30cm, a width of 15cm, a depth of 15cm, and a corresponding central angle of 15°. A soil pressure cell 2 with a diameter of 5cm is arranged at the center of the pressure test groove, and the filler with the same water content and the same compaction degree as that in the pulverization rate test groove is filled around the soil pressure cell. The embedding depth of the soil pressure cell is 1cm, and the soil pressure test range is 50-1000kPa. The purpose of arranging the pressure test groove is to measure the pressure of the rubber roller on the roadbed filler surface, and to determine the size of the counterweight according to the size of the pressure.

[0036] The rubber wheel 6 is a vacuum tire, and a metal hub is used. The vacuum tire is connected with the metal hub, the metal hub is connected with the intermediate bearing through spokes 13, and the intermediate bearing is connected with the driving motor 7 through connecting rods 8. When the driving motor rotates, the rubber wheel rotates around the center of the ring track, and forms a rolling track 9 in the rolling groove 5. When the rubber wheel passes through the pulverization rate test groove, the filler will be loosened and pulverized. When the rubber wheel passes through the pressure test groove, the pressure of the rubber wheel on the filler surface can be measured by the soil pressure cell 2.

[0037] In order to change the pressure of the rubber wheel on the filler surface, the size or number of the counterweight block 10 in the counterweight box 11 can be changed.

[0038] The specific steps of the fine-grained soil pulverization test method are as follows:

[0039] For the convenience of illustration, the full-weathered phyllite (also known as phyllite soil) is taken as an example here. The phyllite soil is very easy to pulverize due to its low cohesion. In order to improve the pulverization performance of the phyllite soil, the red clay with high cohesion can be added to the phyllite soil. The dry mass mixing ratio of the red clay to the phyllite soil can be designed as 5:0, 5:1, 5:2, 5:3 and 5:4, and 40 kg of dry mixed soil of each ratio is prepared. After the fillers of the five ratios are uniformly mixed, the water is added according to the water content of 18% (the optimal water content), and then the mixture is uniformly mixed and placed in a sealed bag for 24 hours. During the 24 hours, the mixture can be stirred 2-3 times in the bag to make the soil particles fully absorb water. The weight of the filler to be added is calculated according to the compaction degree of 89%, 91% and 95% and the volume of the pulverization test tank. The maximum dry density is uniformly taken as 1.70 g / cm 3 . Then the dry densities of the fillers with the three compaction degrees are 1.513 g / cm 3 , 1.547 g / cm 3 and 1.615 g / cm 3 , respectively. The test is divided into groups. In each test group, the fillers are divided into three layers according to the same compaction degree and are compacted by the compaction method in the pulverization test tank. The top surface of the last layer is flush with the other parts of the rolling tank. The pressure test tank has the same compaction degree as the pulverization test tank. During the third compaction, the soil pressure cell is embedded, and the data line of the soil pressure cell is led out of the rolling tank. The soil pressure cell is connected to the data acquisition instrument through the data line to collect the pressure data of the rubber wheel compaction of the filler.

[0040] The surface of the filler in the pulverization test tank 12 is heated by the hair dryer 14, and the surface temperature of the filler is tested by the temperature gun 15. When the temperature reaches 50℃, the heating is maintained for 20 minutes. When the temperature exceeds 50℃, the hair dryer can be moved away from the heating area or turned off. Start the motor, and the rubber wheel rolls in the rolling tank. The soil pressure is recorded by the soil pressure cell 2 and the data acquisition instrument 3. When the soil pressure is not suitable, stop the motor immediately, and change the weight of the weight block 10 in the weight box 11 to change the pressure of the rubber wheel on the surface of the filler. When the measured soil pressure meets the requirements (for example, the standard pressure of the carrying vehicle is 700 kPa), the formal test is started, and the rolling number of the front rubber wheel is counted as the compaction pass number.

[0041] The filler in the pulverization test tank will be loose after compaction. The pulverization rate of the filler is evaluated by testing the dry mass ratio of the loose filler to the dry soil mass in the pulverization test tank. When the compaction pass number reaches 100, the loose soil on the surface of the pulverization test tank is cleaned with a brush and collected. The collected loose soil sample is dried and weighed m d. Let the dry mass of the filler filled in the pulverization test tank be m 0. Then the pulverization rate of the filler is delta=md / m0x100%. The above test method is used for fillers with different proportions to obtain the change rule of different fillers with the change of the proportion, and the proportion with less powdering rate of the filler is used as the optimized proportion.

[0042] The test device and the determination method of the application can quantitatively evaluate the powdering rate of fine-grained soil, and can control the temperature, the rolling times, and the rolling pressure, so that the powdering rates of fillers with different proportions under the same conditions can be quickly evaluated, thereby providing a basis for the selection of fillers.

[0043] The above only describes the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A device for quantitatively testing the pulverization of a roadbed filler, characterized by, The device comprises a ring track, a driving motor, a soil pressure box, a pressure test groove, a pulverization rate test groove, a rubber wheel, a connecting rod, a counterweight box, counterweight blocks and a heating device; the pulverization rate test groove and the pressure test groove are fan-shaped grooves, respectively located on both sides of the ring track, the pulverization rate test groove is used for filling the filler, and the soil pressure box is arranged in the pressure test groove; the driving motor is arranged at the center position of the ring track, the center bearing of the rubber wheel is connected with the connecting rod, the connecting rod is connected with the output shaft of the driving motor, the counterweight box is arranged on the rubber wheel, and the counterweight blocks are arranged in the counterweight box; the heating device comprises a hair dryer and a temperature measuring gun, and is used for drying the filler in the pulverization rate test groove; the width of the ring track is three times the width of the rubber wheel, the rubber wheel can uniformly roll in the ring track, and the filler in the pulverization rate test groove is rolled and rubbed; and the width of the pulverization rate test groove and the pressure test groove is three times the width of the rubber wheel, when the pressure applied by the rubber wheel exceeds the bearing capacity of the filler surface, the filler soil can be extruded from the side of the rubber wheel; the position of the pressure test groove is opposite to the pulverization rate test groove, the central angle corresponding to the pulverization rate test groove is 30°, and the central angle corresponding to the pressure test groove is 15°.

2. The subgrade filler pulverization quantitative testing device according to claim 1, characterized in that, The soil pressure box is located at the center position of the pressure test groove, the embedding depth of the soil pressure box is 1 cm, and the test range of the soil pressure box is 50-1000 kPa; the middle of the rubber wheel is a hub, the hub is connected with the center bearing of the rubber wheel through spokes, and the center bearing is connected with the driving motor through the connecting rod; the periphery of the hub is a rubber tire, the rubber tire is provided with transverse patterns and two longitudinal patterns, and is used for simulating the rolling and friction of the automobile tire on the filler.

3. A method for quantitatively measuring the pulverization of a roadbed filler using the pulverization rate testing device of claim 1, characterized by, The device comprises the following steps: (1) filling the filler with specific proportion, specific moisture content and specific compactness in the pulverization rate test groove, filling the filler with the same proportion, moisture content and compactness in the pressure test groove, and embedding the soil pressure box at a depth of 1 cm below the surface of the filler in the pressure test groove; (2) using the hair dryer to heat the filler in the pulverization rate test groove, starting the driving motor when the temperature reaches 50℃, driving the rubber wheel to make circular motion in the ring track, and rolling and rubbing the fillers in the pulverization rate test groove and the pressure test groove; (3) after a specific rolling number, collecting the loose soil formed in the pulverization rate test groove, drying and measuring the weight, and quantitatively evaluating the pulverization rate of the fine-grained soil by the ratio of the dried loose soil weight to the total mass of the dry soil in the pulverization rate test groove; the optimized proportion is determined by comparing the pulverization rates of fillers with different proportions under the same rolling number, and the pulverization rate is smaller.

4. The method of quantitatively measuring the pulverization of a roadbed filler according to claim 3, characterized by, The mixed soil of the filler is the mixture of the phyllite soil and the red clay with a dry mass mixing ratio of 5:0~5:4, the moisture content is 18%, and the compactness is 89%, 91% or 95%.

5. The method of quantitatively measuring the pulverization of embankment filler according to claim 3, characterized by, The rolling number can be selected as 100, 200 or 300.

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