RU2507341C2 - Method of dynamic probing of soils and device for its realisation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method of dynamic probing of soils, in which a rod with a probe is submerged into soil by means of periodical shocks, and during each shock they determine parameters of soil impact to sensors of the measurement system, providing for amplification of signals from sensors, their analog-digital conversion, registration and transfer of data, including dependence of probe movement on time and dependence of head resistance variation on time, into the outer block of data processing with the help of the appropriate software, as a result of which they determine physical and mechanical characteristics of soil. The probe is submerged into soil with the help of a hydraulic hammer machine. The hydraulic hammer machine after introduction of the rod with the probe is lifted, and the rod is extracted with the probe after introduction of the probe to the specified depth by means of hydraulic hoists. In addition, to measure displacement of the probe during shock, they measure the outer sensor of movement with an autonomous recorder. Data registration is carried out with the help of a recording block adapted for direct connection with the outer block of data processing (computer). To determine soil characteristics, they perform mathematical modelling and solve an inverse problem based on experimental dependences of probe movement on time, variation of head resistance on time and other data.

EFFECT: increased manufacturability, efficiency and depth of research.

Description

The invention relates to the field of construction, namely to the study of the physical and mechanical characteristics of soils by dynamic sounding.

The well-known installation UBP-15M (All-Russian Research Institute of Transport Construction, Guidelines for electrocontact dynamic sounding of soils, Moscow, 1983), in which a probe with a tip and a rod is introduced into the ground using a shock-rope mechanism. The load is lifted by a winch and then dumped. Readings are taken visually. This method has low productivity and a small depth of research. The device that implements the method has large overall dimensions.

Also known hydropercussion machine according to patents No. 2229559 and No. 22252299, which has a fairly high performance and is intended for introduction into the soil of the probe. The weight of the hydraulic shock machine is about 75 kg, while the UBP-15M installation has a mass of 1100 kg. However, this machine cannot implement a method that provides high productivity and depth of research.

From the application for invention No. 2008125936 there is known a method for investigating soils by dynamic sounding selected as the closest analogue, including immersing the probe in the soil by shock and determining the physical and mechanical characteristics of the soil by sensors according to the parameters of the effect of the soil on the sensors, characterized in that the characteristics are determined using calibrated, equipped with mezzose sensors of the measuring electronic system, receiving signals from the sensors, their amplification, conversion to a digital analog code -digital converters (ADC), registration, processing and transmission to the control information block. However, it also does not provide high productivity and depth of research. A device that implements the method and is selected as the closest analogue contains a rod, a probe with a conical tip, a percussion device, means for extracting the probe from the soil, a measuring system located in the probe tip, including sensors, amplifiers, ADCs, a recording unit configured to transmit data to an external information processing unit equipped with software. The device has the same disadvantages as the method implemented therein.

The invention is aimed at solving the problem of improving manufacturability, productivity and depth of research.

The essence of the invention lies in the fact that in the method of dynamic sounding of soils, in which a rod with a probe is immersed in the soil by means of periodic strokes and during each impact, the parameters of the soil influence are determined by the sensors of the measuring system, providing amplification of signals from the sensors, their analog-to-digital conversion, registration and data transfer, including the dependence of the probe’s movement on time, and the dependence of the drag change on time, to an external data processing unit using software, as a result of which the physical and mechanical characteristics of the soil are determined, it is proposed to immerse the probe into the ground using a hydraulic hammer, lift the hydraulic hammer after introducing the rod with the probe, and also remove the rod with the probe after introducing the probe to a predetermined depth with hydraulic lifts, additionally for measure the probe’s displacement upon impact, use an external displacement transducer with an autonomous recorder, record data using the registration unit, It can be directly connected to an external data processing unit (computer), and to determine the soil characteristics, perform mathematical modeling and solve the inverse problem based on the experimental time dependences of the probe displacement, the change in drag from time, and other data.

The essence of the invention also lies in the fact that in a device for dynamic sounding of soil containing a rod, a probe with a conical tip, a striking device, means for extracting the probe from the soil, a measuring system located in the tip of the probe, including sensors, amplifiers, ADCs, a recording unit, made with the ability to transfer data to an external information processing unit equipped with software, it is proposed that the percussion device be made in the form of a hydropercussion machine, means for extracting the probe from the soil and perform it on the basis of hydraulic lifts so that they provide a hydraulic hammer lift after introducing the rod with the probe, as well as removing the rod with the probe after introducing the probe to a predetermined depth, in addition to measure the probe’s movement upon impact, introduce an external displacement sensor with an autonomous recorder, adapt the registration unit for direct connection with an external data processing unit (computer), provide the external data processing unit with software for determining the characteristics of the ground pu topics of mathematical modeling and solving the inverse problem on the basis of experimental dependences of the probe displacement on time, graphs of changes in drag against time and other data.

The use of a miniature electronic recording unit for recording and storing information during sounding, placed in the probe tip, provides high productivity and manufacturability of research. For a more accurate measurement of probe displacement during impact, an external displacement sensor with an autonomous recorder is used. Soil characteristics are determined not by tables, since the tables in SP 11 - 105 - 97 are given only for sandy soils, but according to dynamic sounding and mathematical modeling.

Figure 1 shows a block diagram of a device that implements a method of dynamic sounding of soils. Figure 2 shows a block diagram of the probe tip. Figure 3 shows graphs of changes in the force of drag from a single impact in various types of soils. Figure 4 shows graphs of the movement of the probe from one hit in various types of soils.

The device for dynamic sounding of soils shown in figures 1,2 can be installed, for example, on a car (not shown in the figures). It contains a percussion device (probe immersion device), made on the basis of a water hammer machine. The tip 1 of the probe includes an accelerometer 2 and load cells 3, which are connected to the inputs of the high-speed registration unit - logger 6 using the appropriate connections 4,5. The tip 1 of the probe also has a power supply unit 8 connected to the logger 6 by connection 7. The hydropercussion machine 10 is mounted on the rod 11 and is driven by an oil station not shown in the figures with a control valve 9. At the beginning of the dive, the hydropercussion machine 10 takes its upper initial position, then lowers to the lowest position during the immersion. The transfer of the hydraulic hammer 10 from the lower position to the initial upper position is carried out using hydraulic lifts 13. Hydraulic lifts 13 are also used to remove the rod 11 after the end of the dive. The displacement sensor 12 is used to record the movement diagram of the probe.

During dynamic sounding, the probe tip 1 is introduced into the ground by impacts. Upon impact, accelerations occur. Accelerations are recorded using the accelerometer 2. Strain gauges 3 installed inside the hollow cylinder resting on the conical part of the probe tip 1 record the cone drag force when it is introduced into the ground. Figure 3 shows graphs of changes in drag force in various types of soils. Logger 6 is intended for recording, recording and storing data from accelerometer 2 and strain gauges 3. For this purpose, logger 6 contains an LCP (analog-to-digital converter) and a memory unit not shown in the figures. By integrating the accelerations recorded by the accelerometer 2 over time, it is possible to determine the penetration rate of the probe. Further, if we integrate the accelerations a second time, that is, now the speed is now, we will eventually find out the probe movements in time. Graphs of probe movement over time in various types of soils are shown in Fig. 3.

In the proposed technology, to determine the construction properties of soils, mathematical modeling of the interaction of the probe with the soil is used based on nonlinear soil mechanics and software. Modeling of the stress-strain state of soils, which is used in our technology, is complicated by the fact that it is necessary to solve the inverse problem. In solving the inverse problem, experimental data are used as initial information. We have experimental graphs of the probe moving in time, Fig. 3, graphs of the change in drag in time, Fig. 2 and other data (probe oscillation frequency, impact force, impact acceleration, etc.). Through mathematical modeling, we build similar virtual graphs. Further, by means of optimization calculations, we bring the virtual graphs closer to the experimental ones to a given degree of accuracy. When we succeed, we say that the soil has the same values of the parameters of the building properties as in the virtual model. The software package is designed so that it is possible to describe the movement of the probe tip in the soil environment with obtaining graphs similar to the real dynamic sounding graphs shown in figures 3, 4. By solving the optimization problem, it is possible to maximize the approximation of the calculated graphs to the real ones. If they coincide with acceptable accuracy, they conclude that the soil parameters coincide with the values in the calculation model.

Claims (2)

1. A method of dynamic sounding of soils, in which a rod with a probe is immersed in the soil through periodic strokes and during each impact, the parameters of the soil impact on the sensors of the measuring system are determined, providing amplification of signals from the sensors, their analog-to-digital conversion, registration and data transfer, including dependence of probe movement on time and dependence of drag on time, to an external data processing unit using the appropriate software, as a result those that determine the physical and mechanical characteristics of the soil, characterized in that the probe is immersed in the soil using a hydraulic hammer, lifting the hydraulic hammer after introducing the rod with the probe, and also removing the rod with the probe after introducing the probe to a predetermined depth, are hydraulic lifts, in addition to measure movement when impacting, the probe uses an external displacement sensor with an autonomous recorder, data is recorded using a registration unit adapted for direct connection with an external data processing unit (computer), and to determine the characteristics of the soil, mathematical modeling is performed and the inverse problem is solved on the basis of the experimental time dependences of the probe displacement, the change in drag from time, and other data. 2. A device for dynamic sounding of the soil, containing a rod, a probe with a conical tip, a striking device, means for extracting the probe from the soil, a measuring system located in the tip of the probe, including sensors, amplifiers, ADCs, a recording unit, configured to transmit data to an external unit information processing, equipped with software, characterized in that the percussion device is made in the form of a hydropercussion machine, the means for extracting the probe from the soil are made on the basis of hydraulic lifts t to ensure that they lift the hydraulic shock machine after introducing the rod with the probe, as well as removing the rod with the probe after introducing the probe to a predetermined depth, in addition to measuring the probe’s movement upon impact, an external displacement sensor with an autonomous recorder is introduced, the registration unit is adapted for direct connection with an external data processing unit (computer), the external data processing unit is equipped with software for determining soil characteristics by mathematical modeling and solved I have the inverse problem on the basis of the experimental curves moving the probe from time to time, change the drag from time to time, and other data.

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