CZ304642B6 - Automatic control device of geotechnical machine for measuring load-bearing capacity of the soil and method of working with such a device - Google Patents

Abstract

The automatic control device of geotechnical machine for measuring load-bearing capacity of the soil according to the present invention consists of at least one deviation meter installed on a geotechnical machine (1), an actuator (1.3) installed also on the geotechnical machine (1), a software (3.1) installed on a computer (3), and a bidirectional USB communicator (2). The digital deviation meter is provided with a port, the USB communicator (2) is provided with at least one serial port (2.1, 2.2) connected to deviation meters (1.1, 1.2) provided with a serial ports, and at least one digital deviation meter is performed as a first digital deviation meter for measuring dynamometer deformation and/or a second digital deviation meter for measuring position of a piston/penetration. The USB communicator (2) is intended for transmission of information from the deviation meters (1.1, 1.2) into the computer (3) and for transmission of control commands to the geotechnical machine (1). The connection of the deviation meter (1.1, 1.2) and the USB communicator (2) is implemented through the mediation of a serial cable (4), the connection of the actuator (1.3) with the USB communicator (2) is made through the mediation of a multi-core cable (5) and connection of the USB communicator (2) to the computer (3) is made by means of an USB cable (6). The measurement of load-bearing capacity on the geotechnical machine for measuring load-bearing capacity of the soil with automatic control device is conducted such that a piston of the geotechnical machine (1) moves in the direction to the material to be tested until the instant of its contact therewith, which is identified by the change in deformation being measured by the first digital deviation meter (1.1) for measuring dynamometer deformation and subsequent the piston moves toward the tested material until the instant of achieving a preset penetration, where the actual penetration is measured by the second digital deviation meter (1.2), or until stabilized stress is achieved. Subsequently, the direction of the piston movement changes and the piston returns back in its initial position with zero stress acting on the material under test. Then the piston stops automatically or the cycle repeats. The complete release of stress acting on the material is identified by the achievement of zero value of the first digital deviation meter (1.1) for measuring dynamometer deformation. At the moment of the first contact of the piston with the material under test, all the deviation meters reset to zero and the dynamometer deformation value, being measured by the first digital deviation meter (1.1), is read out regularly during the movement of the piston for various penetration values wherein the measured values are continuously recorded in an output file.

Description

Automatic control device of geotechnical machine for measuring the bearing capacity of soil and method of work with this device

Technical field

BACKGROUND OF THE INVENTION The present invention relates to an automatic control device of a geotechnical machine for measuring the bearing capacity of soil and to a method of working therewith.

BACKGROUND OF THE INVENTION

During construction, whether it is the construction of buildings or roads, it is necessary to check the soil on which construction is to be carried out in terms of its CBR ratio in percent, ie Califomia Bearing Ratio, hereinafter referred to as bearing capacity. This is done using geotechnical testing machines known, for example, under the designation CBR - TS50 or VJT5011, hereinafter referred to as the CBR, ie the Califomia Bearing Ratio, to test the soil sample and determine its bearing capacity. For the current load capacity test, the geotechnical machine is equipped with a piston to lift the sample container continuously, a steel mandrel, which is pushed at a constant speed into the sample, and two mechanical dial gauges to read CBR values, ie penetration depth and force. The geotechnical machine is controlled manually by two switches for moving the piston up and down.

Due to the pan-European trend to refine the design of structures in road construction, there was a need to determine another soil property, namely the modulus of elasticity of soil M _R. The laboratories do not yet have adequate technical equipment for this new test. To meet the increasing demands for design accuracy, it has led to the introduction of an innovative procedure for determining the modulus of elasticity M _R i on geotechnical CBR measuring machines.

The test for the determination of the modulus of elasticity M _R is currently carried out on geotechnical CBR measuring machines. The test for the determination of the modulus of elasticity M _R is carried out after the completion of the resistance test on the same soil sample. In this test, the soil sample is repeatedly loaded and unloaded by a steel mandrel in about 60 cycles for about 4 hours. The soil pattern is moved by the piston mechanics towards and away from the dark using manually operated mechanical switches. When the geotechnical machine is switched on, tm is pushed to the specified maximum deformation depth determined on two mechanical dial gauges and then stopped. Thereafter, the first cycle takes place where the sample is unloaded to a predetermined value and stopped. Subsequently, the geotechnical machine is started and the data from the dial indicators are recorded when the darkness contacts the sample. The geotechnical machine is stopped when tm again reaches the prescribed maximum deformation depth. By recording the data from both dial indicators, the first measurement cycle is completed. This process is repeated according to the type of material in 50 to 70 cycles. Manual determination of the value of the elastic modulus on existing equipment, however, requires high demands on the precision of the operator of the geotechnical machine and its time. Handling a geotechnical machine requires operator skills and experience in reading and recording data from dial indicators, according to which the piston movement is manually controlled in the range of millimeters for about 4 hours.

It is therefore an object of the present invention to provide such a control device that would automate and simplify the measurement of the elastic modulus on a geotechnical machine to measure CBR, as well as a method of working with such a device.

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SUMMARY OF THE INVENTION

To a large extent, the above-mentioned deficiencies are eliminated by the automatic control device of the geotechnical machine for measuring the load capacity of the soil, consisting of at least one dial gauge installed on the geotechnical machine, a driver installed on the geotechnical machine, a USB communicator and software installed on the computer. the dial gauge is provided with a port, the USB communicator is provided with at least one dial gauge port, a controller contact and a computer interface port, wherein at least one digital dial gauge is provided as the first digital dial gauge to measure dynamometer deformation and / or the second digital dial gauge to measure piston / penetration position.

In a preferred embodiment, the connection between the dial indicator and the USB communicator is made via a serial cable, the connection between the controller and the USB communicator is made via a multi-core cable, and the connection between the USB communicator and the computer is made via a USB cable.

The abovementioned drawbacks are also remedied to a large extent by the method of carrying out load-carrying capacity measurements on the soil-carrying geotechnical machine with the automatic control device according to the invention, which consists in moving the piston of the geotechnical machine towards the material to be tested. identified by changing the deflection value measured by the first digital indicator to measure the deformation of the dynamometer, then the piston is stopped and all connected dial indicators are reset, then the piston moves against the test material until the preset penetration is reached, when the current penetration is measured with the second digital dial, until a constant tension is reached, then the direction of movement of the piston is changed and the piston returns to its starting position with zero applied stress on the test material where the piston stops automatically or the cycle is repeated, the complete release of stress on the material being identified by reaching the zero value of the first digital indicator for dynamometer deformation measurement, while during the piston movement the dynamometer deformation value is measured regularly for various penetrations. file.

Overview of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an automatic control device of a geotechnical soil capacity measuring machine according to the invention; and FIG. 2 is a graph of values measured by a geotechnical soil capacity measuring machine provided with an automatic control device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows an automatic control device, indicated by solid lines, of a geotechnical soil bearing capacity measuring machine according to the invention, comprising at least one digital dial indicator having a port installed on a geotechnical machine 1, a controller 1.3 installed on a geotechnical machine 1, a USB communicator 2 and the software 3.1 installed on the computer 3, which in the present case is a program called "CBR Test".

In the present case, a first digital gauge 1.1 is used to measure the dynamometer deformation, i.e., stress, and a second digital gauge 1.2, to measure the piston position, i.e., penetration into the test material. As mentioned above, there may be more of these dial indicators. The first digital dial indicator TT is equipped with port 1.11. The second digital indicator 1.2 has a port 1.12.

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The USB communicator 2 is equipped with ports for connecting the dial indicators, in this case ports 2.1, 22 for connecting the first digital dial indicators 1.1 and the second digital dial indicators 12, a contact 2.3 for connecting a driver 1.3 and a port 2.4 for connecting a computer 3.

In the present case, the ports 2.1, 2.2 for connecting the dial indicators 1.1, 1.2 are designed as serial ports, the contact 2.3 for connecting the computer 3 as a USB port.

The connection between the digital indicators 1.1, 1.2 and the USB communicator 2 is made by means of serial cables 4 of eg RS-232 type. The connection between the controller 1.3 and the USB communicator 2 is made using a multi-core cable 5. The connection between the USB communicator 2 and the port 3.2 of the computer 3 is made using a USB cable 6.

The geotechnical machine 1 is controlled by software 3.1 via a USB communicator 2 and a controller 1.3 provided with three buttons: up, down and stop.

The function of USB Communicator 2 is to connect the dial gauges 1.1,1,2 and driver 1.3 to a computer 3 with a single port 32. The USB Communicator 2 creates 3 virtual ports on the computer which allow the control software 3.1 to communicate easily with two but also more digital dial indicators. The USB communicator 2 also provides control of the outputs for the control of the geotechnical machine by means of signals transmitted from the controller 1.3. Another function of the USB communicator 2 is to safely stop the movement of the piston of the geotechnical machine 1 if the computer 3 for any reason stops communicating.

The operation of the geotechnical machine 1 provided with the automatic control device according to the invention is fully automatic. The tasks that can be performed are tests of any course and using any parameters, such as the standard CBR test, the cyclic CBR test - constant penetration, the cyclic CBR test - constant dynamometer.

Description of each of the above tests:

In the standard CBR test, the sensitivity of the dynamometer to the material contact can be adjusted from 0 to 0.02 mm with an accuracy of 1/1000 mm. After starting the test, the piston first moves towards the material until the piston touches its surface, which is automatically identified by a corresponding change in the deformation value of the first digital dial gauge 1.1 for measuring the dynamometer deformation. Once the value is found, the piston stops and all connected dial gauges are reset. Subsequently, the piston moves against the test material until a preset penetration is achieved, which is constant at 10 mm for this type of test. The current penetration is measured by the second digital indicator 12. During the movement, the deformation value of the dynamometer is measured regularly at different penetrations, which is measured by the first digital indicator. These values are continuously written to the output file, from which at the end of the test an XLS file with the numerical and graphical output of the test is generated. At the end of the test, the piston stops automatically, changes its direction and returns to its starting position.

In the cyclic CBR test with constant penetration, it is possible to set the dynamometer sensitivity to material contact in the range 0 to 0.02 mm with the accuracy 1/1000 mm, the preset penetration value in the range 0 to 10 mm with the accuracy 1/100 mm, constant penetration in the interval 0 to 10 mm with an accuracy of 1/1000 mm, number of cycles to completion of the test in the range of 0 to 100 cycles, graduated after one cycle, material elasticity rate in the range of 0 to 0.05 mm with an accuracy of 1/1000 mm at which the test in progress, or the condition for completion of the test, ie the number of cycles or the degree of elasticity of the material.

After starting the test, the piston first moves towards the material until the piston touches its surface, which is automatically identified by a corresponding change in the defined value on the digital deflection gauges of the first digital dynamometer 1.1. Once given

If the value is found, the piston stops and all connected dial indicators are reset. Subsequently, the piston moves continuously against the test material until a preset penetration is achieved, which is measured by a second digital dial gauge 1.2. In order to find the value of the preset penetration, the movement of the piston is changed and the tension in the material is smoothly released, which is identified by reaching zero of the first digital dial gauge 1.1. The cycle is repeated until a specified degree of elasticity of the material or a specified number of cycles is reached, depending on the test parameter settings. As the piston moves in both directions, the dynamometer deformation value measured by the first digital dial gauge 1.1 is read at various penetrations and is continuously recorded in an output file, from which an XLS file with the numerical and graphical output of the test is generated at the end of the test. At the end of the test, the piston stops automatically, changes direction and returns to its starting position.

For a cyclic CBR test with a constant dynamometer, the sensitivity of the dynamometer to the material contact can be set within the range of 0 to 0.02 mm with an accuracy of 1/1000 mm, or a constant penetration to determine the maximum value of the dynamometer. Values can be entered between 0 and 10 mm with an accuracy of 1/1000 mm. It is also possible to set a constant dynamometer voltage, where the interval of permissible values is limited by the maximum permissible value of the dynamometer and graduated by 1 kPa, the number of cycles to completion of the test in the range 0 to 100 cycles / 1000 mm at which the test in progress is terminated, the condition for terminating the test, ie achieving the number of cycles or reaching the degree of elasticity of the material, and the condition for terminating the cycle, ie achieving constant penetration or constant stress.

After starting the test, the piston first moves towards the material until the piston touches its surface, which is automatically identified by a corresponding change in the defined value of the digital deflection gauges of the first digital dynamometer 1.1. Once the value is found, the piston stops and all connected dial gauges are reset. Subsequently, the piston moves continuously against the test material, depending on the test parameter setting, until a constant penetration is measured, measured by the second digital gauge 1.2, or until a constant voltage is obtained, as measured by the first digital dynamometer 1.1 and calibrated strain and force conversion. . After finding the appropriate reversal value, the movement of the piston will change and the stress in the material will be smoothly identified, which is identified by reaching zero value of deformation gauges of the first digital dynamometer 1.1. The cycle is repeated until a specified degree of elasticity of the material or a specified number of cycles is reached, depending on the test parameter settings. While the piston is moving in both directions, the deformation value of the dynamometer is measured at different penetrations, which is measured by the first digital indicator L1 and is continuously written to the output file, from which the XLS file with the numerical and graphical output of the test is generated. At the end of the test, the piston stops automatically, changes its direction and returns to its starting position. An example of such a graphical output is shown in Fig. 2 in the form of a working diagram. Here, the individual measurement cycles are evident in which the pressure on the test material is increased until the maximum penetration is achieved. When it is reached, the pressure is released to zero and the cycle is repeated.

The first result of the measurement is the determination of the CBR ratio, measured in accordance with current standards in force, at a penetration of 2.5 mm and 5 mm, which corresponds to a smooth part of the load curve of the working diagram until the maximum penetration is achieved. This data is needed to determine the quality of core materials and materials used in road construction layers using a comparative ratio.

The second result is the determination of the deformation characteristic of the E-modulus, measured in MPa, on the basis of the cyclic loading from the deformation value and the stress from the last loading cycle. The value of the modulus of elasticity is needed for numerical modeling and to determine the state of stress and deformation of the structure to dimension the structure.

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In addition, the application interface of the software has a graphical indicator of the test progress and an indicator of the current sample movement, ie the piston. The software also has an interface for setting various parameters - communication ports, directories and files for storing results, dynamometer calibration values, etc.

The automatic control device of the geotechnical machine for measuring the soil capacity according to the invention is easily connectable to all types of existing geotechnical machines intended for CBR measurement on one side and standard computers on the other side, thus extending the utilization of the geotechnical machine to the possibility of determining soil modulus.

As mentioned above, the automatic control system of the invention is applicable in all geotechnical machines for determining the modulus of soil and building materials on a machine commonly used for CBR determination.

Claims (2)

PATENT CLAIMS An automatic control device of a geotechnical machine for measuring the load capacity of a soil, comprising at least one dial gauge installed on a geotechnical machine, a controller installed on a geotechnical machine from a computer equipped with software for automatically controlling a geotechnical machine, the digital dial gauge having a port wherein at least one digital dial gauge as a first digital indicator for measuring the dynamometer deformation and / or a second digital indicator for measuring the position of the piston / penetration, characterized in that it further comprises a bi-directional USB communicator (2), the USB communicator (2) is intended to transmit the dial indicator information (1.1, 1.2) ) to the computer (3), USB communicator (2) is intended for transfer of control commands to geotechnical machine (1), USB communicator (2) is equipped with at least one serial port (2.1, 2.2) connected to the dial indicator (1.1, 1.2) equipped serial p the connection between the dial indicator (1.1, 1.2) and the USB communicator (2) is made via a serial cable (4), the connection between the controller (1.3) and the USB communicator (2) is made via a multi-core cable (5), The USB communicator (2) and the computer (3) are made using a USB cable (6). Method for carrying out a load-bearing capacity measurement on a soil-bearing geotechnical machine with an automatic control device according to claim 1 or 2, wherein the piston of the geotechnical machine (1) moves towards the test material until it is contacted with it, identified by changing the deformation value measured by the first digital indicator (1.1) to measure the dynamometer deformation, then the piston moves against the test material until the preset penetration is reached, when the current penetration is measured by the second digital indicator (1.2), or until a constant tension is reached and return the piston to its starting position with zero applied stress to the test material, where the piston is automatically stopped or the cycle repeats, the complete release of tension on the material being identified by reaching the zero value of the first digital dial gauge (1.1) for measuring dynamometer deformation, characterized in that at the first contact of the piston with the measured material, all the connected gauges are reset, and during the piston movement the dynamometer deformation value is measured regularly for different penetration, measured by the first digital gauge (1.1) and measured values continuously write to the output file.