Device for measuring rotational resistance of uneven rock joint surfaces

Abstract

The laboratory-scale device for measuring the rotational resistance of uneven rock joint surfaces can measure the rotational resistance of uneven rock surfaces. The testing of uneven rock joint surfaces using the aforementioned device has been introduced and named as the rotational process test by the owners of this invention. This experiment can be applied to a variety of uneven joint surfaces, from sedimentary rocks with the weakest surface resistance to igneous rocks with the highest resistance, as well as rock surfaces filled with various compounds, surfaces reinforced with bacteria and chemicals, and acidic rock surfaces. So far, in this field, despite the need for rotational shear strength parameters, which are a possible process between rock blocks, and are required in most discrete element-based numerical software such as UDEC, 3DEC, no method has been presented and no model has been developed or reported. The rotational resistance measuring device was invented to solve a major gap in rock mechanics engineering, namely estimating the rotational resistance of uneven joint surfaces. Due to the possibility of installing and using precise measuring instruments, this device measures important rotational resistance parameters, including the base / joint surface rotational friction angle, rotational torque, maximum rotational force, vertical displacement, and vertical force during testing.

Description

Description of the invention Title of the invention (as stated in the declaration) Device for measuring the rotational resistance of uneven rock joint surfaces Technical background of the relevant invention This invention is related to the fields of geomechanical engineering, mining, and civil engineering, which can estimate the surface roughness of rock joints and ultimately the rotational resistance of uneven rock joints to control deformations and estimate the stability of rock structures in underground spaces, pisang, and rock slopes. Technical problem and stating the objectives of the invention Determining the surface resistance of rock joints is of particular importance for estimating the resistance and stability of the desired rock environment, including underground spaces, dams, sloping rock walls, and caves. Conventional standard methods in geomechanical, civil, mining, and geotechnical projects in general rely on a linear mechanism (i.e., shearing the surface of the joints linearly and in one direction), which, due to changes in the conditions of stress application, changes in the type of mechanism affecting the surface of the joints, differences in the type of failure process created on the surface of the rock joints, and following a different behavioral pattern and shear model, leads to unconventional results and unrealistic estimates of the surface resistance of the rock joints, which in turn causes large errors in calculations, greater instability of the rock environment, and increased costs of maintaining the rock environment. So far, various methods have been presented and sometimes expanded to estimate the surface resistance of uneven rock joints. According to the above article, their basis is linear mechanism, and up to now, neither a method nor a device for rotational measurement of the surface resistance of uneven rock joints has been presented or introduced.Therefore, the effort and purpose of this invention is to respond to this need and provide a device for rotational estimation of rock joint resistance. In other words, the main purpose of this invention is to determine and estimate the rotational resistance of the uneven rock joint surface with a variable joint surface roughness coefficient of any type of rock that includes the rock environment of geomechanical, civil or mining projects. Accordingly, by performing a rotational process test with the aforementioned device, all the resistance parameters of the rock environment and the uneven joint surface in the rotational process of rock blocks or joints between rock and concrete are measured. The conditions of the rock environment are estimated in the most optimal way from both safety and economic points of view, and the type of fracture of the joint surface will also be analyzed to control deformations. A description of the state of the prior art and the history of developments related to the claimed invention. The investigation and determination of the linear resistance of rock joint surfaces by theoretical and experimental methods has been ongoing for a long time, and the existing concepts have been developed based on a series of specific theories that are linear mechanisms. Therefore, to date, a laboratory device for measuring the linear resistance of rock joint surfaces, called a direct rock shear device, and theoretical / experimental relationships in the field of linear resistance have been used to measure the resistance of rock joint surfaces and rock environments. The linear mechanism is intended to ensure that uneven joint surfaces under direct shear testing only affect one specific direction and orientation of the joint surface. However, the existing empirical relationships and methods for estimating the resistance of rock joint surfaces based on direct shear testing have been introduced and presented.In addition, a direct cutting device and linear process testing have been used to evaluate the conditions of the joints of rocks on each other, the cutting conditions and the type of fracture process of uneven joint surfaces, estimate the resistance of the surfaces and in line with that estimate the behavioral model and finally to analyze the stability of underground spaces, surface spaces and rock slopes. It has been assumed and applied to all rock environments and joint surface conditions with any type of governing mechanism on uneven joint surfaces and the concepts have been expanded accordingly and without considering and examining other mechanisms. Based on the evidence and results presented in this field, as the condition of the rock environment and uneven joint surfaces becomes more complex, the output of the surface resistance results will be unreliable and the estimates will not be close to reality and comprehensive. Because the joint surfaces of the rocks are evaluated and analyzed in one direction. By applying normal force and the joint surfaces being locked together, the aforementioned device, due to the limitation and lack of ability and power required to cut the joint surfaces of the rocks, becomes rigid and the ability to perform the cutting stage of the joint surfaces to record other computational parameters of resistance will be impossible and the criterion estimate will be impossible.In previous concepts of surface resistance of uneven joints, whose mechanism and calculation method are linear and whose measuring device is a direct shear device, joint surfaces are much more affected by the speed of normal and shear loading by the operator than the rotational mechanism. The surface resistance measurement device for uneven rock joints evaluates the surface of the joints in a broader way and estimates the parameters related to resistance more comprehensively. Currently, there is no device similar to the surface resistance measurement device for uneven rock joints for rocky environments that can cover the weaknesses of linear devices and estimate and perform estimation in the field of rotational resistance. Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention The joint surface strength measuring device must have high shear force power and strength to examine the joint surfaces of rocks in terms of roughness and roughness in different ranges of low, medium and high of different rocks in order to provide an accurate and comprehensive estimate of the joint surface strength. Accordingly, the rotational resistance measuring device is designed and invented in such a way that by means of a jack applying a rotational shear load, it is possible to cut and subsequently break all types of smooth to very rough joint surfaces of all soft to hard rocks. Also, by means of a jack applying a vertical load, vertical or normal force loading is applied in all three classes, high, medium and low, and there is no limitation in terms of loading.To better understand the conditions of the joint surface of uneven rocks in a real rock environment, it is necessary that the joint surfaces have the greatest contact and coupling surface with each other during the test and affect each other's roughness or roughness. In this context, the rotational resistance measuring device mounts the joint surfaces of the rocks together using two metal molds located under the automatic manual jack, and the maximum locking and contact surface can be created from zero to any desired value by the normal force applying jack. The rotational shear force applying jack installed on the left side of the device can record the shear displacement (called rotational displacement in the test related to the device) more than any other measurement method, and this maximum displacement is also due to the high power of the device's jack. In other words, the device for measuring the rotational resistance of uneven joint surfaces has more freedom of action and use, and provides better estimates of fracture, shear, and surface behavior patterns of the joints, and calculates important and fundamental parameters to reach the actual resistance value, which refers to the accuracy of the device's measurement.The bearing with the highest resistance to pressure and force is selected to rotate the lower metal mold, which is located inside the graduated plate, and the rotation rate is recorded by the graduated plate as the device rotates. However, based on the concept of anisotropy, which is that rock surfaces and uneven joint surfaces behave differently in different directions and directions, and that in the direct shear test device, due to device limitations, joint surface samples cannot be tested and examined in all directions and directions, the rotational resistance measuring device performs a comprehensive evaluation in terms of resistance according to its relevant test by extending the fracture and shearing of the joint surface to the plane and a step of rotating the joint surfaces in the XOY plane on each other, and provides an estimate of the parameters and measurements of the resistance of the joint surface affected by the conditions of all directions and directions of the joint surface and unevenness. The rotation and rotational shearing action is completed by the bearing under the metal mold or the bottom of the device with the help of a jack applying a rotational force to this process.On the other hand, if the necessary facilities and equipment are available, the rotational resistance measuring device can be upgraded from a mechanical field to a dynamic field, which can be used simultaneously to estimate the rotational resistance of the uneven joint surface by writing a specialized program and automating the device and designing related software, using both mechanical and dynamic fields, a capability that has not been seen in a direct shear testing device to date. Finally, the rotational resistance measuring device for uneven stone joint surfaces is located in the center of a sturdy metal frame, where the upper metal plate or mold of the device is connected to a jack that applies normal force to the center of the device, and below it, the lower plate of the device is equipped with a bearing with shear resistance and very high specifications, which is located inside a graduated plate that measures changes in shear displacement, and the entire set is also installed on a base so that the loading operation is applied by both jacks at the most optimal height distance of the metal mold.Of course, the jack for applying the rotational shear force is installed on the left side of the device inside the main frame and the tip of the jack is connected to a frictionless and sliding groove to move the bottom of the device and create a rotation action. In other words, the upper metal mold of the device must remain in a fixed position due to the normal loading on it and the rotation action must be applied to the bottom of the device and the effects must be recorded. In the third to sixth figures, which are the drawings of the parts of the device, it is clear with what thickness and strength the device is made to be resistant to all loads and not damaged. To control the device during the test, for better performance of the device in presenting the results, a metal mold (gutter number 8) that encloses the upper metal mold has been used. Explanation of shapes, maps and diagrams This section of the description of the invention is devoted to a brief description of the figures and drawings of the invention. Therefore, for a better understanding and comprehension of the measuring mechanism of the device, the method of conducting the experiment, measuring the resistance parameters and describing the specifications of the device, the drawings presented in the "drawing file" are briefly explained. The general shape of the device and the parts of the device, with the details and final dimensions of each part, are briefly presented in the two-dimensional and three-dimensional pdf file of the drawing, which, respectively, includes the following figures. Figure 1) is a three-dimensional schematic diagram of the entire device assembly in the form of separate, disassembled and numbered parts, based on which the parts are measured, and the device molds and the main column of the device are identified as 1-3 and 2-3, then the bearing, the graduated plate, the part connected to the mold, part of which is placed inside the bearing, and finally the device jacks, which include the rotating shear force jack bases, the frictionless groove piece, and the circular piece on which the rotating shear force jack is installed. Figure 2) is a three-dimensional, black-and-white schematic of the device, which describes its overall components by numbering them and the precise specifications of each part. The device parts include a vertical force application jack, an upper metal mold, a lower metal mold, an axial piece connecting the metal mold and bearings, bearings, a graduated plate, a rotating shear load application jack, a rotating shear jack support base, a general support base for the device for installation, and the main column of the device. Figure 3) is a template map for placing samples of uneven joint surfaces, which specifies in what format and dimensions the joint surface sample should be prepared. Figure 4) The piece connecting the upper metal mold of the device to the jack applies a normal load to the surface of the stone joints. Figure 5) is related to the graduated plate for measuring the angle of rotation, which is located under the molds or trays of the device, and the desired bearing is also placed inside it. Figure 6) Schematic of the sliding groove into which the jack tip is placed and moves, and also includes the jack support components for applying rotational load. A clear and precise statement of the advantages of the claimed invention over prior inventions. The advantages of the invented uneven joint surface resistance measuring device include the following. More freedom of operation of the device for cutting uneven seam surfaces, High strength and power of the device in applying normal and rotational stress loading, Estimation of the rotational resistance of the joint surface with different ranges of roughness (low, medium and high), The maximum amount of displacement during rotation of the joint surfaces over each other, The entire joint surface is affected during the rotational process test, Measurement and evaluation of the surface resistance of joints in all directions and orientations, Revising and completing behavioral patterns, cutting mechanisms, and joint surface failure processes, The most accurate estimate of joint surface resistance compared to other methods, Providing the most optimal safety and economic conditions in related mining and construction projects,  Ability to upgrade the device from mechanical to dynamic mode. Description of at least one implementation method for implementing the invention A- Working mechanism of the device: The rotational mechanism of discontinuities or unevenness of the rock joint surface for calculating the surface resistance is different from the linear mechanism in terms of the failure conditions, the way of applying stresses, the deformations of the joint surface resulting from the test, and the amount of shear resistance to prevent shear corrosion to create the required stability. The measurement of rotational resistance by the developed device includes two stages of locking the joint surfaces and rotating the joint surface, which are necessary to estimate the rotational resistance of the uneven joint surface and complete the rotational test process of both stages above. These two stages occur in a continuous and fast process that can also be considered simultaneously. In accordance with these stages, two loading forces play a fundamental role, one of which is the vertical loading force that is applied perpendicular to the rock joint surface and the other is the rotational loading force that is applied horizontally and along the width of the rock joint surface on the desired joint surface, which will cause the joint surfaces to rotate.The magnitude and ratio of the two perpendicular loading forces depend greatly on the shape and geometry of the joint surfaces, and the angle of rotation of the joint surface plays an important role in estimating the rotational resistance. The angle of rotation of the joint surface, which indicates the amount of displacement of the surfaces on each other, will vary depending on the type of rock and the roughness of the joint surface to counteract the rotation and shear of the rock joint surface. Therefore, it is necessary to accurately record the angle of rotation and the rotational force that causes and drives the rotation of the joint surfaces. B- How to perform a laboratory test according to the working mechanism: At the beginning of each laboratory test and before starting the test, the selection of a rock sample is of particular importance, which requires determining the context and dimensions of the project and the type of prevailing rock environment in order to calculate and measure the rotational resistance of the uneven joint surface. Rock joint samples can be natural or joints created in the tensile failure process or artificial joints that are used in the rotational process test. Test samples from the joint surfaces are placed in special molds with a high-strength concrete mortar that has high tensile and compressive strength and low permeability. These molds allow for the metal jaw of the cutting machine to be placed in the normal and shear stress field. According to the concepts presented for measuring rotational resistance, initially normal loading is applied to the uneven joint surfaces. For this purpose, the prepared samples are placed inside the measuring device and then measuring gauges are placed on the upper surface to record the vertical or normal displacement affected by the normal loading to record the smallest displacement changes. Finally, by turning on the normal load jack and placing the jack in the loading mode, the first stage of the test, i.e., by placing the normal on the joint surfaces, is performed, and the important parameters of this stage for estimating the resistance are recorded with the highest accuracy. Next, by installing an iron frame at an appropriate height on the main frame of the device and enclosing the upper floor of the device inside the iron frame in order to control the destructive stresses applied to the test jacks, shear control of the uneven joint surfaces for greater effect and to prevent the joints of the stones from protruding on each other, the rotational test enters the second stage of loading, i.e., rotational loading and rotation of the joint surfaces, and the second group of parameters, which are considered to be vital parameters of resistance, are recorded.By rotating the surface of the joints and thereby rotating the bottom of the device by the jack, the amount of change in the angle of rotation of the surface of the joints is recorded by the device's display arrow on the graduated plate embedded under the device, which by including the effect of the dimensions of the joint surface, the amount of rotational displacement of the surfaces can be estimated and the amount of applied rotational force can also be recorded. The test steps of the uneven surface of the joints are subjected to normal loading in several periods (three or five periods) at different stress levels from low to high. Figures number five and six of the figure file, the initial results of estimating the rotational resistance parameters are presented in the form of a graph. Finally, based on the values ​​of the obtained parameters, the rotational resistance of the uneven stone joint surface is measured. Explicit mention of the industrial application of the invention The main field to which the invented device is related is the field of rock engineering or rock mechanics, which is applicable in the field of controlling large-scale earth deformations, real understanding of the conditions of rock environments, determining and modifying behavioral patterns and models of rock environments, and investigating the processes of cutting and fracture of joint surfaces, which plays the role of estimating and measuring the rotational resistance of uneven joint surfaces more than any other field. Ground control is the analysis of the maintenance and stability of tunnels and underground spaces through combined mechanical processes, the main controller of which is the shear behavior of the rock joints adjacent to the structure. In this regard, the possibility of rotation of rock blocks, especially in the vicinity of the underground structure, is possible due to the induced stress field and the free surface created. Surface mining fields, including the stability of mine walls, extraction stairs, and underground mining, including the stability of mining galleries, the stability and maintenance of extraction workshops, as well as determining the limits of firework, and to prevent ground subsidence, increasingly require accurate estimation and measurement of the resistance of uneven rock joint surfaces under various loading conditions, especially rotational loading. In the field of geomechanical engineering, in the field of underground drilling to access minerals and gas and oil reservoirs, as well as in the field of design and analysis of oil and gas reservoirs for their control and maintenance, estimating the rotational resistance of the surface of rock joints seems necessary and essential to make decisions and evaluate the rock environment around structures with a more comprehensive view. A device for measuring the rotational resistance of uneven joint surfaces in the field of civil engineering in various projects, including the stability of stone slopes, to prevent slope collapse and control possible hazards due to the separate stress conditions prevailing in each area of ​​rock environments, requires an accurate estimate of the resistance of the joint surfaces for better stability. In addition to the above, another area where the use of a device for measuring the rotational resistance of uneven joint surfaces can be utilized and valuable results can be provided for controlling the surrounding conditions is the field of civil engineering in the field of dam construction, in order to stabilize the rock environment under the foundation of dams in the best possible way, and even neutralize the walls and dam walls, which are likely to be subjected to excessive stresses, and control the tectonic stresses around them.

Claims

Claim What is claimed: Claim 1) Design and manufacture of a new rock joint rotational resistance measuring device capable of measuring rotational displacement and rotation of the joint surface around the central axis of the joint surface and radially. This device includes: a counterclockwise rotating box or cell, rotary and vertical loading arms, a combined mechanical and automatic loading system, a vertical, rotary displacement and rotation angle measuring system. Claim 2) According to claim 1, the box or cell of the device is trapezoidal in shape and the internal dimensions of each of the upper and lower boxes are respectively equal to: large base 17 cm, small base 3.5 cm, box width 13.5 cm and height 7 cm. The lower box or cell is fully rotatable and rotates around the center of the box, which, depending on the type of stone and its material, is allowed to rotate from 1 to 35 degrees, which is equivalent to 31 mm of rotational displacement. The upper box is set upright and its displacement is also adjusted in the vertical direction. Claim 3) According to claims 1 and 2, the device's displacement measurement system measures vertical displacement with an accuracy of 0.01 and rotational displacement of the joint surface with an accuracy of 0.

001. Claim 4) According to claim 1, the loading system and the execution of the rotation mechanism for measuring the rotational resistance of the rock joint surfaces are designed and adjusted in such a way that they are capable of rotational loading on all types of rock joint surfaces (from weak to very strong) and include a normal force application arm, a rotational force application arm and a special rotary table for rotating any type of rock joint surface from slightly to very rough and hard. Thus, it is possible to rotate the uneven rock joint surfaces on each other due to the locking of the upper and lower cells and due to the presence of roughness that was uncontrollable and impossible until now. Claim 5) The loading system of the device according to claim 1 is of a mechanical and automatic type, and the loading capacity of its load-applying arms is 1000 kilonewtons. Claim 6) The vertical and rotational load application arms are measured by the device with an accuracy of 20 Newtons in accordance with claim 1. Claim 7) According to claim 1, the device can test the sample under conditions of constant vertical loading (CNL) and constant vertical stiffness (CNS) and then add a rotational load to the test conditions and apply a rotational shear in addition to these standard conditions. In other words, this device can test the joints in the state and mechanism of rotation on each other by considering all the standard conditions of shear test, including boundary conditions and loading conditions, by applying a standard rotational load. Claim 8) According to claim 1, the process of measuring rotational resistance can be performed in two cycles of initial or normal loading and rotational loading on the surfaces of rock joints, during which various parameters such as vertical force, vertical displacement, rotation angle, rotational force during the process, and the rotational mechanism can be accurately measured for the surface of rock joints.

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