WO2024060380A1 - Rotary friction coefficient measurement method and system based on annular loading - Google Patents

Abstract

Disclosed in the present invention are a rotary friction coefficient measurement method and system based on annular loading. The method comprises: measuring and determining a position to be tested and measured, drilling a hole by means of a rotary drilling rig to a designed elevation or a bedrock position to be measured, and cleaning the hole to ensure that no sludge is present at the bottom of the hole; mounting an annular loading module at the bottom of the rotary drilling rig, and lowering a rotary drilling bit to sink the annular loading module to the surface of said bedrock position; applying vertical pressures to the annular loading module in a graded mode by means of a vertical pressurizing module, measuring values of the applied vertical pressures by means of a vertical pressure measurement module, and measuring a settlement value of a rotary drilling rod by means of a rotary drilling rod settlement amount measurement module; applying torque loads to the annular loading module in a graded mode, and monitoring and obtaining torque values by means of a torque load measurement module; repeatedly carrying out single-point annular loading module torsional friction coefficient measurement tests multiple times under different vertical pressures, and substituting into a rock mass friction coefficient calculation formula for a rock mass bearing stratum to obtain a rock mass friction coefficient value of a rock mass bearing stratum to be measured. The test cost is low, and the safety is high.

Description

A method and system for measuring the rotational friction coefficient based on circular loading Technical field

The invention belongs to the technical field of friction coefficient measurement, and more specifically, relates to a rotary friction coefficient measurement method and system based on annular loading.

Background technique

The friction coefficient refers to the ratio of the friction force between two surfaces to the vertical force acting on one surface. It is related to the roughness of the surface and has nothing to do with the size of the contact area; when there is relative sliding between objects, the sliding friction is called Dynamic friction; sliding friction when objects have a tendency to slide but have not yet slid is called static friction; depending on the nature of motion, the friction coefficient can be divided into kinetic friction coefficient and static friction coefficient; there is currently a lack of special equipment on the market for testing sliding friction between two objects Coefficient device; for two materials that need to be rotated and fitted together, it is very important to measure the friction coefficient during the process of joining and rotating. However, most existing friction coefficient measuring devices lack the ability to measure the coefficient of friction. The ability to test the friction coefficient of the joint surface by rotating is very inconvenient when measuring the friction coefficient of two materials that are attached and rotated, which in turn wastes a lot of time and is not conducive to the measurement of the friction coefficient.

As the terminal of load transmission for suspension bridges, the anchorage structure's load-bearing capacity and reliability are crucial. The gravity anchor relies on its own load and the friction of the foundation to bear the horizontal component of the tension on the main cable. It has the characteristics of strong applicability. The selection of gravity anchor as the anchor for large-span suspension bridges has become a trend. If the friction resistance between the gravity anchor concrete and the bedrock surface is insufficient, it will easily affect the bearing capacity of the anchor foundation, thereby threatening the safety of the bridge. The accurate value of the anti-slip friction coefficient of the anchor base is particularly important. According to the specification requirements, there must be no settlement or relative slippage between the anchorage and bedrock of the suspension bridge under the action of the main cable tension. Therefore, after the excavation of the anchorage foundation pit is completed, in-situ tests are often conducted on the friction coefficient of the bearing layer bedrock. The usual engineering practice is to combine the engineering geological conditions of the bedrock at the bottom of the anchor foundation, conduct a direct shear test on the contact surface between the anchor concrete and the rock mass at the elevation of the bearing layer of the anchor foundation, and combine the indoor rock mass mechanical test results to Based on the current relevant regulations, specifications, and industry standards, a reasonable value for the friction coefficient is finally determined.

Currently, the existing friction coefficient measurement technology is carried out after the foundation pit excavation is completed to verify the rationality and safety of the design scheme and parameter values. This verification process requires sufficient space to carry out the test work; if the actual measured values are relatively large, If the design parameters are small, the value of the design parameters is too large, and the safety factor of the scheme is low. The design needs to be changed to expand the excavation depth of the anchorage, or to add anchors and anchor cables to the base. If the measured value is larger than the design parameters, it means that the design is not the optimal scheme. It will inevitably cause waste. In addition, for major engineering projects, reasonable parameter values are carried out in the early design stage, which is crucial to the rational selection of the entire design and construction plan, and is even directly related to the entire project investment and construction scale; therefore, there is an urgent need for a method that can be used during the project survey stage. It can directly test and accurately obtain the friction coefficient of the rock mass in the bearing layer, and is a low-cost, high-safety, and significant testing method for the friction coefficient of the rock mass in the bearing layer.

Contents of the invention

In view of the above defects or improvement needs of the existing technology, the present invention provides a rotary friction coefficient measurement method and system based on annular loading, which uses a rotary drilling rig to drill holes to the design elevation or the bedrock position to be measured, clear the hole and ensure that the hole is There is no mud at the bottom; install the annular loading module to the bottom of the rotary drilling rig, lower the rotary drill bit to sink the annular loading module to the surface of the bedrock to be measured at the bottom of the hole; apply vertical pressure to the annular loading module in stages through the vertical pressure module. The applied vertical pressure value is measured through the vertical pressure measurement module, and the settlement value of the rotary drill pipe is measured through the rotary drill pipe settlement measurement module; the torque load is applied to the annular loading module in stages, and the torque value is monitored and obtained through the torque load measurement module ; Repeat multiple single-point annular loading module torsional friction coefficient test experiments under different vertical pressures, and substitute the rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain the measured rock mass friction coefficient value of the rock mass bearing layer; the present invention The friction coefficient of the rock mass of the bearing layer can be obtained through direct testing during the project investigation phase, and the test is low-cost, highly safe, and of great significance.

In order to achieve the above objects, one aspect of the present invention provides a rotary friction coefficient measurement method based on annular loading, which includes the following steps:

S1: Measure and determine the location to be tested, and the rotary drilling module drills holes to the design elevation or the location of the bedrock to be tested; after the hole is formed, the hole cleaning module cleans the hole to ensure that there is no mud at the bottom of the hole;

S2: While the hole cleaning operation continues uninterrupted, install the annular loading module to the bottom of the rotary drilling module. After the installation of the annular loading module is completed, pull out the cleaning pipe, lower the rotary drill bit, and sink the annular loading module to the bottom of the hole. The bedrock surface to be tested;

S3: Install a vertical pressure measurement module on the rotary drill pipe, apply vertical pressure to the annular loading module in stages through the vertical pressure module, and measure the applied vertical pressure value through the vertical pressure measurement module. The settlement measurement module measures the settlement value of the rotary drill pipe. After the settlement of the rotary drill pipe reaches a stable level, the output pressure of the vertical pressure module is kept constant and the vertical pressure measurement module is removed;

S4: The power unit on the rotary drill pipe applies torque load to the annular loading module in stages. When torsional sliding suddenly occurs, the torque value is monitored and obtained through the torque load measurement module located in the power unit;

S5: Repeat steps S3 and S4 to carry out multiple single-point annular loading module torsional friction coefficient test experiments under different vertical pressures, substitute the rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain the friction coefficient and calculate the average value, and obtain The friction coefficient value of the rock mass in the bearing layer of the measured rock mass.

Further, the friction coefficient f of the rock mass bearing layer in step S5 is calculated by the following formula:

Among them, f is the friction coefficient of the rock mass in the rock mass bearing layer; T is the stable output torque value of the annular loading module; N is the vertical pressure value of the annular loading module; D is the outer diameter of the annular loading plate; d is the annular loading plate. Loading plate inner diameter.

Further, step S3 also includes the vertical pressure module applying vertical pressure to the rotary drill pipe in 1 to 3 levels, applying a first-level load every 5 minutes, and measuring the settlement amount of the rotary drill pipe immediately after each load is applied. The measurement module reads the settlement value of the rotary drill pipe after loading. When the difference between the settlement values of the rotary drill pipe measured twice in a row does not exceed 0.01mm, it is determined that the settlement of the rotary drill pipe has reached stability.

Further, step S4 also includes: applying the torque load in 8 to 12 levels according to the estimated maximum torque value. When the torsion angle caused by the application of the torque load increases significantly, increase the torsion load level; the torque load application method adopts time control. Method, apply one level every 5 minutes of stabilization.

Another aspect of the present invention provides a rotary friction coefficient measurement system based on annular loading, including a rotary drilling module, an annular loading module, a vertical pressure module, and a vertical pressure measurement module located on the rotary drilling module. module, rotary drill pipe settlement measurement module and torque load measurement module; among which,

The torque load measurement module is located in the power unit of the rotary drilling module; the vertical pressure module applies vertical pressure to the rotary drilling module in stages, and uses the gravity of the rotary drilling module to provide The reaction force transmits the generated vertical pressure to the annular loading module. The annular loading module exerts vertical pressure on the lower measured rock mass to cause settlement. The settlement occurs through the rotary drilling rod installed on the rotary drilling module. The measurement module real-time monitors the settlement value generated by the annular loading module under each level of load condition, and measures the vertical pressure value exerted by the vertical pressure module in real time through the vertical pressure measurement module on the rotary drilling module; through the vertical pressure measurement module on the rotary drilling module The power unit applies a torque load to the annular loading module, and the torque value is monitored in real time through the torque load measurement module located in the power unit; by carrying out multiple torsional friction tests of the annular loading module under different vertical pressure values, it is substituted into the rock mass bearing layer The rock mass friction coefficient calculation formula calculates the friction coefficient and calculates the average value to obtain the rock mass friction coefficient value of the measured rock mass bearing layer.

Further, the rotary drilling module includes a rotary drill rod, a drilling rig mast connected to the rotary drill rod, a power unit connected to the rotary drill rod and the drilling rig mast, and a power unit located on the rotary drilling rig. A rotary drill bit that digs the bottom of the drill pipe.

Further, the annular loading module includes a connecting end plate connected to the bottom of the rotary drill bit and an annular loading plate connected to the connecting end plate;

The connecting end plate is a circular plate with a thickness of not less than 10cm;

The circumferential side of the connecting end plate is evenly spaced with a plurality of bolt holes for mounting the connecting end plate to the bottom of the rotary drill bit;

The annular loading plate is a tubular concrete member;

The bottom surface of the annular loading plate can be in close contact with the rock mass to be measured.

Further, the vertical pressure measurement module includes multiple sets of strain gauges provided on the rotary drill pipe;

The rotary drill pipe settlement measurement module is implemented by installing a laser displacement sensor on the drilling rig mast.

Further, the laser displacement sensor is located on the bottom side of the drilling rig mast for real-time monitoring of the settlement value of the rotary drill pipe produced by the vertical pressure module under each load condition;

The strain gauges are evenly installed on the surface of the rotary drill pipe, and each group of strain gauges is located on the same horizontal section of the rotary drill pipe.

Further, the torque load measurement module uses a torque sensor for real-time monitoring of the torque load value and torsion angle of each stage of the torque output of the power unit;

The torque load value is applied in 8 to 12 levels according to the estimated maximum torque value. When the torsion angle caused by the application of torque load increases significantly, the torsion load level is increased;

The torque load is applied to the next level every 5 minutes of stability. When torsional sliding suddenly occurs, record the torque value of the previous level that caused sudden torsional sliding.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

(1) A rotary friction coefficient measurement system and method based on annular loading of the present invention uses a rotary drilling module to rotary drill holes, a vertical pressure module to apply vertical pressure to the rotary drilling module in stages, and the rotary drilling module is used to rotary drill holes. The gravity of the excavation and drilling module provides a reaction force, which transmits the vertical pressure generated to the annular loading module. The annular loading module exerts vertical pressure on the lower measured rock mass to cause settlement, and the settlement measurement module of the rotary drill pipe is used in real time. Monitor the settlement value produced by the rotary drill pipe under each load level, measure the vertical pressure value exerted by the vertical pressure module through the vertical pressure measurement module, and apply torque load to the annular loading module through the power unit on the rotary drill pipe. , monitor the torque value in real time through the torque load measurement module located in the power unit; repeat multiple single-point annular loading module torsional friction coefficient test experiments under different vertical pressures, and substitute them into the rock mass friction coefficient calculation formula of the rock mass bearing layer Obtain the friction coefficient value of the rock mass in the bearing layer of the measured rock mass; the existing friction coefficient measurements are carried out after the foundation pit excavation is completed, and sufficient space is required to carry out the test work. During the test process, the measured values are often different from the designed values. Parameters are difficult to unify, and the construction plan adjustment process is cumbersome. However, this invention can directly test and obtain the friction coefficient of the rock mass of the bearing layer during the project survey stage. Compared with the traditional measurement method, the test cost is low, the safety is high, and the design plan can be supported. powerful.

(2) A rotary friction coefficient measurement system and method based on annular loading of the present invention is suitable for different water level conditions and can also be carried out in an artificial water soaking environment; if the water level is buried in a shallow underwater operating environment, reverse reaction is used The circulation drilling rig rotary cuts the bottom of the borehole flat, replaces the drill bit with an annular loading plate rotating friction device, and then conducts a loading friction test on the bearing layer; if the water level is buried deep in a dry operating environment, after the hole is completed, follow up the steel From the casing to the bottom, the test surface is manually processed to meet the flatness and undulation required by the test.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic structural diagram of a rotary friction coefficient measurement system based on annular loading according to an embodiment of the present invention;

Figure 2 is a schematic diagram of the installation structure of a strain gauge of a rotary friction coefficient measurement system based on annular loading according to an embodiment of the present invention;

Figure 3 is a schematic diagram of the installation structure of a torque sensor of a rotary friction coefficient measurement system based on annular loading according to an embodiment of the present invention;

Figure 4 is a schematic structural diagram of an annular loading module of a rotary friction coefficient measurement system based on annular loading according to an embodiment of the present invention;

Figure 5 is a schematic structural diagram of an annular unit of an annular loading module of a rotary friction coefficient measurement system based on annular loading according to an embodiment of the present invention;

Figure 6 is a schematic diagram of the working state of rotary drilling using a rotary friction coefficient measurement method based on annular loading according to the embodiment of the present invention;

7 is a schematic diagram of a hole cleaning state of a method for measuring a rotational friction coefficient based on annular loading according to an embodiment of the present invention;

Figure 8 is a schematic diagram of the working state of the annular loading module of a rotary friction coefficient measurement method based on annular loading according to the embodiment of the present invention;

9 is a schematic diagram of the installation of strain gauges and the application of vertical loads in a method for measuring a rotational friction coefficient based on annular loading according to an embodiment of the present invention;

Figure 10 is a schematic diagram of the torque load application state of a rotary friction coefficient measurement method based on annular loading according to the embodiment of the present invention;

FIG. 11 is a schematic flow chart of a method for measuring a rotational friction coefficient based on annular loading according to an embodiment of the present invention.

In all drawings, the same reference numerals represent the same technical features, specifically: 1-rotary drilling module, 11-rotary drill pipe, 12-drilling rig mast, 13-power unit, 14-rotary drill bit, 2-annular loading module, 21-connecting end plate, 22-annular loading plate, 23-bolt hole, 3-vertical pressure module, 4-vertical pressure measurement module, 41-strain gauge, 5-rotary drill Rod settlement measurement module, 51-laser displacement sensor, 6-torque load measurement module.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. In addition, the technical features of various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not restricted by the sequence of steps and/or structural composition mode, but must be in the form of It is based on what a person of ordinary skill in the art can realize. When the combination of technical solutions appears to be contradictory or cannot be realized, it should be considered that such combination of technical solutions does not exist and is not within the protection scope required by the present invention.

In the description of the present invention, it should be noted that, unless expressly stated otherwise, when an element is referred to as being "fixed to", "disposed on" or "provided to" another element, it can be directly on the other element. element or indirectly on another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element; the terms "mounted," "connected," "connected," "provided with" " should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or it can be an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediary, it can It is the internal connection between two elements or the interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

As shown in Figures 1-4, one aspect of the present invention provides a rotary friction coefficient measurement system based on annular loading, which is used in conjunction with a rotary drilling rig to measure the surface friction coefficient of the measured bearing layer, including rotary drilling. Drilling module 1, hole cleaning module, annular loading module 2, vertical pressure module 3, vertical pressure measurement module 4, rotary drill pipe settlement measurement module 5 and torque load provided on the rotary drilling module 1 Measurement module 6; use the rotary drilling module 1 to rotary drill holes to the design elevation or the bedrock position to be measured; use the vertical pressure module 3 to apply vertical pressure to the rotary drilling module 1 in stages, using The rotary drilling module 1's own gravity provides a reaction force and transmits the vertical pressure generated to the annular loading module 2. The annular loading module 2 exerts vertical pressure on the lower measured rock mass to cause settlement. Through installation The rotary drill pipe settlement measurement module 5 on the rotary drilling module 1 monitors the settlement value generated by the annular loading module 2 under each load level in real time, and the vertical pressure measurement module 4 on the rotary drilling module 1 measures the vertical pressure in real time. The vertical pressure value applied to the pressurizing module 3; the torque load is applied to the annular loading module 2 through the power unit of the rotary drilling module 1, and the torque value is monitored in real time through the torque load measurement module 6 located in the power unit; multiple times are carried out (At least 5 sets of tests) Torsional friction test of annular loading module under different vertical pressure values. Substitute into the formula for calculating the friction coefficient of the rock mass bearing layer to obtain the friction coefficient and calculate the average value to obtain the measured bearing layer rock. (Soil) body friction coefficient value; the present invention can directly test and obtain the friction coefficient of the bearing layer rock mass during the project survey stage. Compared with the traditional measurement method, the test cost is low and the safety is high.

Further, as shown in Figures 1 to 4, the rotary drilling module 1 includes a rotary drill pipe 11, a drilling rig mast 12 connected to the rotary drill pipe 11, and at the same time, the rotary drill pipe 11 and The power unit 13 connected to the drilling rig mast 12 and the rotary drill bit 14 located at the bottom of the rotary drill pipe 11; the rotary drilling module 1 is used to rotary drill holes to the design elevation or the bedrock location to be measured; The rotary drilling rod 11 has sufficient rigidity to control the elastic distortion deformation of the rod itself during torsion.

Further, as shown in Figures 1 to 4, the annular loading module 2 is an annular end plate structure that can be installed at the end of the rotary drilling bit 14, which is a collection of multiple annular units 24; the annular loading module 2 includes a connecting end plate 21 connected to the bottom of the rotary drilling bit 14 and an annular loading plate 22 connected to the connecting end plate 21; the connecting end plate 21 is a circular steel plate with a thickness of not less than 10 cm; a plurality of bolt holes 23 are evenly spaced on the circumferential side of the connecting end plate 21, which are used to install the connecting end plate 21 to the bottom of the rotary drilling bit 14 by bolt connection; the annular loading plate 22 is a tubular concrete member, and when working, the bottom is close to the surface of the bearing layer of the rock mass to be measured; the side of the rotary drilling bit 14 maintains a certain distance from the hole wall to avoid friction between the hole wall and the annular loading module 2; the bottom surface undulation difference of the annular loading plate 22, the loading surface undulation difference of the rock mass (or rock and soil, hereinafter referred to as rock mass) to be measured, the number of test groups, etc. all meet the requirements of the "Engineering Rock Mass Test Method" The annular loading plate 22 is in close contact with the rock mass to be measured in accordance with the requirements of the "GBT 50266-2013" standard.

Further, as shown in Figures 1 to 4, the vertical pressure module 3 is used to perform graded vertical pressure on the annular loading module 2; the vertical pressure measurement module 4 is used to measure the vertical pressure. The vertical pressure exerted by the pressurizing module 3 on the annular loading module 2; the vertical pressure measurement module 4 includes multiple sets of strain gauges 41 provided on the rotary drill pipe 11; the rotary drill pipe The settlement measurement module 5 is used to measure the settlement value of the rotary drilling rig, which is achieved by installing a laser displacement sensor 51 on the drilling rig mast 12; the laser displacement sensor 51 is installed on the bottom side of the drilling rig mast 12, and is used to measure the settlement value of the rotary drilling rig. In real-time monitoring, the settlement value of the rotary drill pipe 11 produced by the vertical pressurizing module 3 under each load condition is also the settlement value of the annular loading module 2 or the measured rock mass; by The vertical pressure module 3 exerts vertical pressure on the rotary drill pipe 11 in stages, uses the gravity of the rotary drill pipe 11 to provide reaction force, and transmits the pressure to the annular loading module 2 to apply pressure to the rock mass. Vertical pressure is applied to cause the rotary drill pipe 11 to settle, and the pressure value is kept constant until the settlement value stabilizes; the laser displacement sensor 51 installed at the bottom of the drilling rig mast 12 is used to monitor the pressure generated by the rotary drill pipe 11 under each load level in real time. Settlement value; fix the laser displacement sensor 51 on the drilling rig mast 12 of the rotary drilling rig to monitor the settlement amount of the rotary drilling rod 11 under each level of load when the vertical pressurizing module 3 is pressurized. When the same level of load conditions When the displacement difference of the rotary drill pipe 11 within the next 5 minutes does not exceed 0.01mm, it is determined that the settlement of the rotary drill pipe 11 reaches the maximum value and the pressure value is kept constant; the strain gauges 41 are preferably in 4 groups and are evenly installed on the The surface of the rotary drill pipe 11, and each set of strain gauges 41 are located on the same horizontal section of the rotary drill pipe 11, for real-time monitoring of the application of the vertical pressure module 3 to the rotary drill pipe 11. vertical pressure;

Further, as shown in Figures 1 to 4, the torque load measurement module 6 adopts a torque sensor, and applies a torque load to the measured rock mass in stages through the power unit 13, and monitors the torque load value and torsion angle of each level of torque output of the power unit 13 in real time through the torque sensor arranged in the power unit 13; the torque load value is applied in 8 to 12 levels according to the estimated maximum torque value, and when the torsion angle caused by the application of the torque load increases significantly, the torsion load grade can be appropriately increased; during the torque load application process, the vertical pressure must always be kept constant; the torque load application method adopts a time control method, and the next level is applied every 5 minutes of stability until a torsional slip suddenly occurs, and the torque value T of the previous level before the sudden torsional slip of the equipment is recorded, indicating that slip friction damage occurs under the torque value T; when approaching friction sliding, pay close attention to the changes in the rotation angle and torque value of the drill rod of the rotary drilling rig.

As shown in FIGS. 5 to 11 , another aspect of the present invention provides a method for measuring a rotational friction coefficient based on annular loading, which is used to measure the friction coefficient of a rock mass bearing layer, and comprises the following steps:

S1: Measure and determine the predetermined position to be tested, and the rotary drilling module drills to the designed elevation or the position of the bedrock to be tested; after the hole is formed, the hole cleaning module cleans the hole to ensure that there is no mud residue at the bottom of the hole; specifically, it includes measurement and layout, measurement and determination of the predetermined position to be tested; the rotary drilling module drills the hole, and the rotary drilling rig drills the hole to the designed elevation or the position of the bedrock to be tested; during the drilling process, a steel casing is lowered by a puller to prevent the hole from collapsing, and the steel casing should be followed to the bottom of the hole; the inner diameter of the steel casing is larger than the outer diameter of the annular loading plate device to avoid friction on the side wall; the hole cleaning module cleans the hole, and after the rotary drilling rig drills the hole, the reverse circulation hole cleaning operation is carried out to clean the friction surface and ensure that there is no mud residue at the bottom of the hole; for water-containing holes, the catheter is connected on-site, and the air lift reverse circulation hole cleaning method is used to clean the hole;

S2: While the hole cleaning operation continues uninterrupted, install the annular loading module to the bottom of the rotary drilling module. After the installation of the annular loading module is completed, pull out the cleaning pipe, drill down the rotary drill bit and sink it to the bottom of the hole. Design elevation position; the annular loading module is an annular end plate that can be installed at the end of a rotary drill bit, including a connecting end plate connected to the bottom of the rotary drill bit and an annular loading plate connected to the connecting end plate; annular The bottom of the loading plate includes multiple annular units;

S3: Install a vertical pressure measurement module on the rotary drill pipe. Use the vertical pressure module to apply vertical pressure to the rotary drill pipe in stages and transfer it to the annular loading module. Measure and obtain the applied vertical pressure through the vertical pressure measurement module. The vertical pressure value is measured through the rotary drill pipe settlement measurement module and the settlement value of the rotary drill pipe is obtained. After the settlement of the rotary drill pipe reaches a stable value, the output pressure of the vertical pressurization module is kept constant and the vertical pressure is removed. Measurement module; specifically, multiple sets of strain gauges are pasted on the same horizontal section of the rotary drill pipe, and vertical pressure is applied to the rotary drill pipe through the vertical pressure module and transferred to the annular loading module, and through the laser displacement sensor Read the settlement value of the rotary drill pipe in real time. After the settlement of the rotary drill pipe reaches a stable level, keep the output pressure of the vertical pressurization module constant and remove the strain gauge; the vertical pressure module controls the vertical pressure of the rotary drill pipe. The application is divided into 1 to 3 levels, using the time control method, applying a level of load every 5 minutes. Immediately after each load is applied, the settlement value of the rotary drill pipe after loading is read through the laser displacement sensor. When the reading is performed twice in a row, When the difference in the settlement value of the rotary drill pipe does not exceed 0.01mm, after determining that the settlement of the rotary drill pipe has reached stability, keep the output pressure of the vertical pressurization module constant and remove the strain gauge connection line;

S4: Apply torque load to the annular loading module in stages through the power unit on the rotary drill pipe until torsional sliding suddenly occurs. Monitor and obtain the torque value in real time through the torque load measurement module located in the power unit; the torque load is the estimated maximum The torque value is applied in 8 to 12 levels. When the torsion angle caused by the application of torque load increases significantly, the torsion load level can be appropriately increased; the torque application method adopts the time control method, applying one level every 5 stable minutes until sudden torsion occurs. Sliding, record the torque value T at this time, indicating that sliding friction occurs under the torque value T; when approaching friction sliding, pay close attention to the changes in the rotary drill pipe rotation angle and torque value;

S5: Repeat steps S3 and S4 to carry out multiple single-point annular loading module torsional friction coefficient test experiments under different vertical pressures, substitute the rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain the friction coefficient and calculate the average value, and obtain The friction coefficient value of the rock mass in the bearing layer of the tested rock mass; repeat steps S3 and S4 to carry out no less than 5 single-point repeated friction coefficient tests under different vertical pressures. If the extreme values of multiple sets of test data are not greater than the average 30% of the value, take the average value as the friction coefficient measurement result of the measuring point; among them, when the annular loading module rotates at a certain speed, due to the action of the base friction, torque is generated on the annular loading module, and the torque generated by different vertical pressures different;

The loading stable output torque value T of the annular loading module is calculated by formula (1):

∫ _A τ ρ dA＝T (1)

Among them, dA is the area of the annular element at the bottom of the annular loading plate; τ is the base shear stress of the annular element; ρ is the distance from the annular element to the central axis of the annular loading plate; A is the area of the annular loading plate; ∫ is the integral sign;

The area dA of the annular unit at the bottom of the annular loading plate is equal to the product of the annular perimeter of the annular unit and the radial width of the annular unit, calculated by formula (2):

dA＝2πρdρ (2)

Among them, dA is the area of the annular unit at the bottom of the annular loading plate; dρ represents the width of the annular unit; ρ is the distance from the annular unit to the central axis of the annular loading plate; d is the inner diameter of the annular loading plate;

The base shear stress τ of the annular element is equal to the product of normal stress and friction coefficient, and is calculated by equation (3):

Where, f is the friction coefficient of the rock mass bearing layer; N is the vertical pressure value of the annular loading module; A is the area of the annular loading plate;

It can be seen from equations (1) and (3) that the loading stable output torque value T of the annular loading module can also be expressed by equation (4):

Among them: A is the area of the annular loading plate; f is the friction coefficient of the rock mass in the rock mass bearing layer; N is the vertical pressure value of the annular loading module; D is the outer diameter of the annular loading plate; d is the inner diameter of the annular loading plate; ∫ is integral symbol;

The area A of the annular loading plate is expressed by equation (5):

Among them, D ³ -d ³ =(Dd)(D ² +Dd+d ² ), D is the outer diameter of the annular loading plate, d is the inner diameter of the annular loading plate, both are known quantities; through equations (4) and ( 5) It can be seen that the friction coefficient of the rock mass in the rock mass bearing layer is calculated by equation (6):

Among them, T is the loading stable output torque value of the annular loading module; N is the vertical pressure value of the annular loading module; D is the outer diameter of the annular loading plate; d is the inner diameter of the annular loading plate;

In summary, by measuring the idling torque value of the annular loading module, the loading stable output torque value of the annular loading module, the vertical pressure value of the annular loading module, the outer diameter D of the annular loading plate, and the inner diameter d of the annular loading plate, it can be calculated The friction coefficient of the rock mass in the rock mass holding layer at the bottom of the annular loading module is obtained; the annular loading module is subject to different vertical pressures, and different rotational torque values can be measured, but the measured friction coefficient is a constant value. (Group test) Torsional friction test of annular loading module under different vertical pressure values. Find the average friction coefficient, which is the bedrock friction coefficient value, and you can obtain the friction coefficient value of the measured bearing layer rock (soil) body.

The working principle of the rock mass friction coefficient testing system and method of the rock mass holding layer based on the annular loading rotary friction coefficient measuring system of the present invention: through the rotary drilling module 1, the drilling is rotary drilled to the design elevation or to the desired height. Measuring the bedrock position; applying vertical pressure to the rotary drilling module 1 through the vertical pressure module 3, using the gravity of the rotary drilling module 1 to provide reaction force, and passing the generated vertical pressure through the The power unit 13, the rotary drill pipe 11, and the rotary drill bit 14 are transmitted to the annular loading module 2. The annular loading module 2 exerts vertical pressure on the lower measured rock mass to cause settlement. Through installation The laser displacement sensor 51 at the bottom of the drilling rig mast 12 monitors the settlement value of the rotary drill pipe 11 under each load level in real time, and measures the vertical pressure value exerted by the vertical pressure module through the strain gauge 41 on the rotary drill pipe; The torque load is applied to the annular loading module 2 through the power unit 13 on the rotary drill pipe 11, and the torque value is monitored in real time through the torque sensor provided in the power unit 13; multiple times (at least 5 sets of tests) are carried out under different vertical pressure values. The torsional friction test of the annular loading module is carried out by substituting the friction coefficient calculation formula of the rock mass bearing layer into the rock mass friction coefficient calculation formula to obtain the friction coefficient and calculating the average value, and the friction coefficient value of the measured bearing layer rock (soil) body can be obtained; A rotary friction coefficient measurement system and method based on annular loading is suitable for different water level conditions and can also be carried out in an artificial water soaking environment; if the water level is buried in a shallow underwater operating environment, a reverse circulation drilling rig is used to rotate the bottom of the borehole. Cut it flat, replace the drill bit with an annular loading plate rotating friction device, and then conduct a loading friction test on the bearing layer; if the water level is buried deep in a dry operating environment, after the hole is completed, follow the steel casing to the bottom, and manually The test surface is processed to meet the flatness and undulation required by the test; this invention can directly test and obtain the friction coefficient of the rock mass of the bearing layer during the project survey stage. Compared with the traditional measurement method, the test cost is low and the safety is high. .

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements, etc., made within the spirit and principles of the present invention, All should be included in the protection scope of the present invention.

Claims (9)

1. A rotary friction coefficient measurement method based on annular loading, which is characterized by including the following steps:

   S1: Measure and determine the location to be tested, and the rotary drilling module drills holes to the design elevation or the location of the bedrock to be tested; after the hole is formed, the hole cleaning module cleans the hole to ensure that there is no mud at the bottom of the hole;

   S2: While the hole cleaning operation continues uninterrupted, install the annular loading module to the bottom of the rotary drilling module. After the installation of the annular loading module is completed, pull out the cleaning pipe, lower the rotary drill bit, and sink the annular loading module to the bottom of the hole. The bedrock surface to be tested;

   S3: Install a vertical pressure measurement module on the rotary drill pipe, apply vertical pressure to the annular loading module in stages through the vertical pressure module, measure the applied vertical pressure value through the vertical pressure measurement module, and use the rotary drill pipe to The settlement measurement module measures the settlement value of the rotary drill pipe. After the settlement of the rotary drill pipe reaches a stable level, the output pressure of the vertical pressure module is kept constant and the vertical pressure measurement module is removed;

   S4: The power unit on the rotary drill pipe applies torque load to the annular loading module in stages. When torsional sliding suddenly occurs, the torque value is monitored and obtained through the torque load measurement module located in the power unit;

   S5: Repeat steps S3 and S4 to carry out multiple single-point annular loading module torsional friction coefficient test experiments under different vertical pressures, substitute the rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain the friction coefficient and calculate the average value, and obtain The friction coefficient value of the rock mass in the bearing layer of the measured rock mass;

   Among them, the friction coefficient f of the rock mass in the rock mass bearing layer is calculated by the following formula:

   

   Among them, f is the friction coefficient of the rock mass in the rock mass bearing layer; T is the stable output torque value of the annular loading module; N is the vertical pressure value of the annular loading module; D is the outer diameter of the annular loading plate; d is the annular loading plate. Loading plate inner diameter.
2. A rotary friction coefficient measurement method based on annular loading according to claim 1, characterized in that step S3 also includes the vertical pressure module applying vertical pressure to the rotary drill pipe in 1 to 3 levels, Apply a first-level load every 5 minutes. Immediately after each load is applied, the settlement value of the rotary drill pipe after loading is read through the rotary drill pipe settlement measurement module. When the difference between the settlement values of the rotary drill pipe measured twice in a row does not exceed When 0.01mm, the settlement of the rotary drill pipe is judged to be stable.
3. According to a method for determining a rotational friction coefficient based on annular loading as described in claim 2, it is characterized in that step S4 also includes: the application of the torque load is divided into 8 to 12 levels according to the estimated maximum torque value, and when the torsion angle caused by the application of the torque load increases significantly, the torsion load classification is increased; the torque load application method adopts a time control method, and applies one level every 5 minutes of stability.
4. A rotary friction coefficient measurement system based on annular loading, characterized in that it is used to implement a rotary friction coefficient measurement method based on annular loading as described in any one of claims 1-3, including rotary drilling Module (1), an annular loading module (2), a vertical pressure module (3), a vertical pressure measurement module (4), and a rotary drill pipe settlement measurement provided on the rotary drilling module (1) module (5) and torque load measurement module (6); where,

   The torque load measurement module (6) is located in the power unit of the rotary drilling module (1); the vertical pressure module (3) applies vertical pressure to the rotary drilling module (1) in stages. Pressure, using the gravity of the rotary drilling module (1) to provide reaction force, conducts the generated vertical pressure to the annular loading module (2), and the annular loading module (2) exerts force on the lower measured rock mass Settlement occurs due to vertical pressure. The settlement value generated by the annular loading module (2) under each level of load condition is monitored in real time through the rotary drill pipe settlement measurement module (5) installed on the rotary drilling module (1). The vertical pressure measurement module (4) on the excavation drilling module (1) measures the vertical pressure value exerted by the vertical pressurization module (3) in real time; the annular loading module (2) is loaded through the power unit of the rotary excavation drilling module (1). ) applies a torque load, and monitors the torque value in real time through the torque load measurement module (6) located in the power unit; by carrying out multiple torsional friction tests of the annular loading module under different vertical pressure values, it is substituted into the rock mass of the rock mass bearing layer The friction coefficient calculation formula calculates the friction coefficient and calculates the average value to obtain the friction coefficient value of the rock mass in the bearing layer of the measured rock mass.
5. A rotary friction coefficient measurement system based on annular loading according to claim 4, characterized in that the rotary drilling module (1) includes a rotary drill pipe (11) and the rotary drill pipe (11). 11) The connected drilling rig mast (12), the power unit (13) connected to the rotary drilling rod (11) and the drilling rig mast (12) at the same time, and the power unit (13) provided at the bottom of the rotary drilling rod (11) Rotary drill bit (14).
6. A rotary friction coefficient measurement system based on annular loading according to claim 5, characterized in that the annular loading module (2) includes a connecting end plate connected to the bottom of the rotary drilling bit (14) (21) and an annular loading plate (22) connected to the connecting end plate (21);

   The connecting end plate (21) is a circular plate with a thickness of not less than 10cm;

   The circumferential side of the connecting end plate (21) is evenly spaced with a plurality of bolt holes (23) for mounting the connecting end plate (21) to the bottom of the rotary drill bit (14);

   The annular loading plate (22) is a tubular concrete member;

   The bottom surface of the annular loading plate (22) can be in close contact with the rock mass to be measured.
7. A rotary friction coefficient measurement system based on annular loading according to claim 6, characterized in that the vertical pressure measurement module (4) includes multiple groups of sensors arranged on the rotary drilling rod (11). Strain gauge(41);

   The rotary drill pipe settlement measurement module (5) is implemented by installing a laser displacement sensor (51) on the drilling rig mast (12).
8. A rotary friction coefficient measurement system based on annular loading according to claim 7, characterized in that the laser displacement sensor (51) is provided on the bottom side of the drilling rig mast (12) for real-time monitoring. The settlement value produced by the vertical pressure module (3) on the rotary drill pipe (11) under each load level;

   The strain gauges (41) are evenly installed on the surface of the rotary drill pipe (11), and each group of strain gauges (41) are located on the same horizontal section of the rotary drill pipe (11).
9. A rotary friction coefficient measurement system based on annular loading according to claim 8, characterized in that the torque load measurement module (6) adopts a torque sensor for real-time monitoring of each component of the power unit (13). Torque load value and torsion angle of stage torque output;

   The torque load value is applied in 8 to 12 levels according to the estimated maximum torque value. When the torsion angle caused by the application of torque load increases significantly, the torsion load level is increased;

   The torque load is applied to the next level every 5 minutes of stability. When torsional sliding suddenly occurs, record the torque value of the previous level that caused sudden torsional sliding.

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