CN115217166B - Rotary friction coefficient measuring method and system based on annular loading - Google Patents
Rotary friction coefficient measuring method and system based on annular loading Download PDFInfo
- Publication number
- CN115217166B CN115217166B CN202211140441.2A CN202211140441A CN115217166B CN 115217166 B CN115217166 B CN 115217166B CN 202211140441 A CN202211140441 A CN 202211140441A CN 115217166 B CN115217166 B CN 115217166B
- Authority
- CN
- China
- Prior art keywords
- module
- rotary drilling
- annular loading
- rotary
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
Abstract
The invention discloses a rotary friction coefficient measuring method and a rotary friction coefficient measuring system based on annular loading, wherein the method comprises the following steps: measuring and determining a detection position to be tested, drilling a hole to a designed elevation or a bedrock position to be tested by a rotary drilling rig, cleaning the hole and ensuring that no sludge exists at the bottom of the hole; installing an annular loading module to the bottom of the rotary drilling rig, and lowering a rotary drilling bit to sink the annular loading module to the surface of the bedrock to be tested at the bottom of the hole; applying vertical pressure to the annular loading module in a grading manner through the vertical pressurizing module, measuring the applied vertical pressure value through the vertical pressure measuring module, and measuring the settlement value of the rotary drilling rod through the rotary drilling rod settlement measuring module; applying torque loads to the annular loading module in a grading manner, and monitoring and obtaining a torque value through a torque load measuring module; repeatedly carrying out a plurality of times of single-point annular loading module torsional friction coefficient test tests under different vertical pressures, and carrying the test results into a rock mass friction coefficient calculation formula of a rock mass bearing layer to obtain the value of the rock mass friction coefficient of the tested bearing layer; the test cost is low and the safety is high.
Description
Technical Field
The invention belongs to the technical field of friction coefficient measurement, and particularly relates to a rotary friction coefficient measurement method and system based on annular loading.
Background
The coefficient of friction is the ratio of the friction between two surfaces to the vertical force acting on one surface, and is related to the roughness of the surface and not to the size of the contact area; the sliding friction is called dynamic friction when objects slide relatively; the sliding friction when there is a tendency to slide between objects but not yet slide is called static friction; depending on the nature of the movement, the coefficient of friction can be divided into a dynamic coefficient of friction and a static coefficient of friction; the current market lacks a device specially used for testing the sliding friction coefficient between two objects; for two materials which need to rotate and stick together, it is very important to measure the friction coefficient during the process of sticking and rotating, but most of the existing friction coefficient measuring devices lack the capability of measuring the friction coefficient of the joint surface in a rotating manner, so that the measurement of the friction coefficient of two materials which stick together and rotate is very inconvenient, and a great deal of time is wasted to be unfavorable for the measurement of the friction coefficient.
The anchorage structure is used as a terminal for load transmission of the suspension bridge, and the bearing capacity and reliability of the anchorage structure are very important. The gravity type anchorage bears the horizontal component of the tension on the main cable by means of self bearing and the frictional resistance of the foundation, has the characteristic of strong applicability, and has become a trend for the selection of the gravity type anchorage as the anchorage of a large-span suspension bridge. If the friction resistance between the gravity type anchorage concrete and the surface of the bedrock is insufficient, the bearing capacity of the anchorage foundation is easily influenced, the safety of the bridge is further threatened, and the accurate value of the anti-sliding friction coefficient of the anchorage substrate is particularly important. According to the standard requirements, under the action of bearing the tension of the main cable, the suspension bridge anchorage and the bedrock cannot settle or slide relatively. Therefore, after excavation of the anchorage foundation pit is completed, in-situ test is often performed on the friction coefficient of the foundation rock of the bearing stratum. The general practice in engineering is to combine the engineering geological conditions of the foundation bedrock of the anchorage foundation, carry out the direct shear test of the contact surface of the anchorage concrete and the rock body at the elevation of the bearing layer of the anchorage foundation, combine the indoor rock mechanical test achievement, and finally determine the reasonable value of the friction coefficient on the basis of referring to the current relevant regulations, specifications and industry standards.
The existing friction coefficient measuring technology is developed after foundation pit excavation is finished to verify the reasonability and safety of a design scheme and parameter values, and the test work can be carried out only by having enough field in the verification process; if the actual measurement value is smaller than the design parameter, the value of the design parameter is larger, the safety factor of the scheme is low, the design needs to be changed to enlarge the anchorage excavation depth, or an anchor rod and an anchor cable are additionally arranged on the base; if the actually measured value is larger than the design parameter, it indicates that the design is not the optimal scheme, and waste is caused. In addition, for major engineering projects, reasonable parameter values are taken in the early design stage, the selection of the rationality of the whole design and construction scheme is crucial, and even the investment and construction scale of the whole project are directly related; therefore, a method for testing the friction coefficient of the rock mass bearing stratum rock mass, which can directly test and accurately obtain the friction coefficient of the bearing stratum rock mass in a project investigation stage, has low test cost, high safety and great significance, is urgently needed.
Disclosure of Invention
Aiming at the defects or improvement requirements of the prior art, the invention provides a rotary friction coefficient measuring method and system based on annular loading, wherein a rotary drilling rig is used for drilling a hole to a designed elevation or a bedrock position to be measured, cleaning the hole and ensuring that no sludge exists at the bottom of the hole; installing an annular loading module to the bottom of the rotary drilling rig, and lowering a rotary drilling bit to sink the annular loading module to the surface of the bedrock to be tested at the bottom of the hole; applying vertical pressure to the annular loading module in a grading manner through the vertical pressurizing module, measuring the applied vertical pressure value through the vertical pressure measuring module, and measuring the settlement value of the rotary drilling rod through the rotary drilling rod settlement measuring module; applying torque loads to the annular loading module in a grading manner, and monitoring and obtaining a torque value through a torque load measuring module; repeatedly carrying out a plurality of times of single-point annular loading module torsional friction coefficient test tests under different vertical pressures, and carrying the test results into a rock mass friction coefficient calculation formula of a rock mass bearing layer to obtain the value of the rock mass friction coefficient of the tested bearing layer; the method can directly test and obtain the friction coefficient of the rock mass of the bearing stratum in the project investigation stage, and has the advantages of low test cost, high safety and great significance.
In order to achieve the above object, an aspect of the present invention provides a circular loading-based rotational friction coefficient measuring method, including the steps of:
s1: measuring and determining a detection position to be tested, and rotary excavating a drilling module to drill a hole to a designed elevation or a bedrock position to be tested; after the hole is formed, the hole cleaning module cleans the hole to ensure that no sludge exists at the bottom of the hole;
s2: under the continuous uninterrupted state of hole cleaning operation, mounting an annular loading module to the bottom of the rotary drilling module, after the annular loading module is mounted, pulling out the hole cleaning guide pipe, and lowering a rotary drilling bit to sink the annular loading module to the surface of the bedrock to be detected at the bottom of the hole;
s3: installing a vertical pressure measuring module on the rotary drilling rod, applying vertical pressure to the annular loading module in a grading manner through the vertical pressurizing module, measuring the applied vertical pressure value through the vertical pressure measuring module, measuring the settlement value of the rotary drilling rod through the rotary drilling rod settlement measuring module, keeping the output pressure of the vertical pressurizing module constant after the settlement of the rotary drilling rod is stable, and removing the vertical pressure measuring module;
s4: applying torque loads to the annular loading module in a grading manner through a power unit on the rotary drilling rod, and monitoring and obtaining a torque value through a torque load measuring module arranged in the power unit when torsional slip is suddenly generated;
s5: and (4) repeatedly carrying out multiple times of single-point annular loading module torsional friction coefficient test tests under different vertical pressures according to the steps S3 and S4, substituting the test results into a rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain friction coefficients and calculating an average value, so as to obtain the friction coefficient value of the rock mass of the tested bearing layer.
Further, the rock mass friction coefficient of the rock mass bearing stratum in the step S5
Calculated by the following formula:
wherein the content of the first and second substances,
the coefficient of friction of the rock mass of the body bearing stratum; t is a loading stable output torque value of the annular loading module;
the vertical pressure value borne by the annular loading module is obtained;
is the outer diameter of the annular loading plate;
is an annular load plate inner diameter.
Further, the step S3 further comprises the step of applying vertical pressure of the rotary drilling rod by the vertical pressurizing module in 1-3 levels, applying a first-level load every 5 minutes, immediately reading the sedimentation value of the rotary drilling rod after loading by the rotary drilling rod sedimentation amount measuring module after each load application, and judging that the sedimentation amount of the rotary drilling rod is stable when the sedimentation value difference of the rotary drilling rod measured and read continuously twice is not more than 0.01 mm.
Further, step S4 further includes: applying the torque load according to the estimated maximum torque value of 8-12 grades, and increasing the grade of the torsional load when the torsional angle caused by applying the torque load is obviously increased; the torque load application method adopts a time control method and applies the torque load to the first stage every 5 minutes of stability.
The invention provides a rotary type friction coefficient measuring system based on annular loading, which comprises a rotary drilling module, an annular loading module, a vertical pressurizing module, a vertical pressure measuring module, a rotary drilling rod settlement measuring module and a torque load measuring module, wherein the annular loading module, the vertical pressurizing module, the vertical pressure measuring module, the rotary drilling rod settlement measuring module and the torque load measuring module are arranged on the rotary drilling module; wherein the content of the first and second substances,
the torque load measuring module is arranged in a power unit of the rotary drilling module; the vertical pressurizing module applies vertical pressure to the rotary drilling module in a grading manner, the rotary drilling module provides counter force by utilizing the self gravity of the rotary drilling module, the generated vertical pressure is transmitted to the annular loading module, the annular loading module applies vertical pressure to a lower measured rock mass to generate settlement, a settlement value generated by the annular loading module under each grade of load condition is monitored in real time through a rotary drilling rod settlement measuring module arranged on the rotary drilling module, and the vertical pressure value applied by the vertical pressurizing module is measured in real time through the vertical pressure measuring module on the rotary drilling module; applying torque load to the annular loading module through a power unit of the rotary drilling module, and monitoring a torque value in real time through a torque load measuring module arranged in the power unit; and carrying out a plurality of times of torsional friction tests of the annular loading module under different vertical pressure values, and taking the torsional friction tests into a calculation formula of the rock mass friction coefficient of the rock mass bearing layer to obtain the friction coefficient and calculate an average value to obtain the value of the friction coefficient of the rock mass of the tested bearing layer.
Furthermore, the rotary drilling module comprises a rotary drilling rod, a drilling machine mast connected with the rotary drilling rod, a power unit connected with the rotary drilling rod and the drilling machine mast, and a rotary drilling bit arranged at the bottom of the rotary drilling rod.
Further, the annular loading module comprises a connecting end plate connected with the bottom of the rotary drilling bit and an annular loading plate connected with the connecting end plate;
the connecting end plate is a circular plate, and the thickness of the connecting end plate is not less than 10cm;
a plurality of bolt holes for mounting the connecting end plate to the bottom of the rotary drilling bit are uniformly arranged on the circumferential side surface of the connecting end plate at intervals;
the annular loading plate is a tubular concrete member;
the bottom surface of the annular loading plate can be closely attached to the rock mass to be measured.
Further, the vertical pressure measuring module comprises a plurality of groups of strain gauges arranged on the rotary drilling rod;
the rotary drilling rod settlement measuring module is realized by arranging a laser displacement sensor on the mast of the drilling machine.
Furthermore, the laser displacement sensor is arranged on the side surface of the bottom end of the mast of the drilling machine and used for monitoring a settlement value generated by the rotary drilling rod under each stage of load condition of the vertical pressurizing module in real time;
the strain gauges are uniformly arranged on the surface of the rotary drilling rod, and each group of strain gauges are positioned on the same horizontal section of the rotary drilling rod.
Further, the torque load measuring module adopts a torque sensor and is used for monitoring the torque load value and the torsion angle output by each level of torque of the power unit in real time;
applying the torque load value in 8-12 grades according to the estimated maximum torque value, and increasing the grade of the torsional load when the torsional angle caused by applying the torque load is obviously increased;
the torque load Shi Jiaan was applied to the next stage every 5 minutes of stabilization and when a sudden torsional slip occurred, the previous stage torque value at which the sudden torsional slip occurred was recorded.
In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:
(1) According to the rotary friction coefficient measuring system and method based on annular loading, a hole is drilled by a rotary drilling module in a rotary drilling manner, vertical pressure is applied to the rotary drilling module in a grading manner through a vertical pressurizing module, counter force is provided by the self gravity of the rotary drilling module, the generated vertical pressure is transmitted to the annular loading module, the annular loading module applies vertical pressure to a lower measured rock mass to generate settlement, a settlement value generated by a rotary drilling rod under each grade of load condition is monitored in real time through a rotary drilling rod settlement measuring module, and the vertical pressure value applied by the vertical pressurizing module is measured through the vertical pressure measuring module; applying torque load to the annular loading module through a power unit on the rotary drilling rod, and monitoring a torque value in real time through a torque load measuring module arranged in the power unit; repeatedly carrying out a plurality of times of single-point annular loading module torsional friction coefficient test tests under different vertical pressures, and carrying the test results into a rock mass friction coefficient calculation formula of a rock mass bearing layer to obtain the value of the rock mass friction coefficient of the tested bearing layer; the existing friction coefficient measurement is carried out after foundation pit excavation is finished, and the test work can be carried out only by having enough field, the measured value in the test process is often difficult to unify with the design parameter, the adjustment procedure of the construction scheme is complicated, but the friction coefficient of the rock mass of the bearing stratum can be directly measured and obtained in the project investigation stage, and compared with the traditional measurement method, the method has the advantages of low test cost, high safety and strong supporting effect of the design scheme.
(2) The rotary friction coefficient measuring system and method based on annular loading are 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 operation environment, a reverse circulation drilling machine is adopted to cut the bottom of a drilled hole in a rotary mode to be flat, a drill bit with an annular loading plate rotary friction device is replaced, and then loading friction testing is carried out on the bearing layer; if the water level buries the darker dry operation environment, after accomplishing based on the pore-forming, follow the steel and protect a section of thick bamboo to the bottom, handle the test surface by the manual work to satisfy the roughness and the undulation difference of experimental requirement.
Drawings
FIG. 1 is a schematic structural diagram of a rotary friction coefficient measuring system based on circular loading according to an embodiment of the present invention;
FIG. 2 is a schematic view of a mounting structure of a strain gauge of a rotary friction coefficient measuring system based on annular loading according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an installation structure of a torque sensor of a rotary friction coefficient measuring system based on annular loading according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a circular loading module of a circular loading-based rotational friction coefficient measuring system according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a ring unit of a ring loading module of a rotary friction coefficient measuring system based on ring loading according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a rotary drilling operation state of the rotary friction coefficient measuring method based on annular loading according to the embodiment of the invention;
FIG. 7 is a schematic diagram of a hole cleaning state of a circular loading based rotational friction coefficient measurement method according to an embodiment of the present invention;
FIG. 8 is a schematic view of the working status of the circular loading module of the circular loading-based rotational friction coefficient measuring method according to the embodiment of the present invention;
FIG. 9 is a schematic diagram of the installation and vertical load application states of a strain gauge based on a circular loading rotary friction coefficient measurement method according to an embodiment of the present invention;
FIG. 10 is a schematic diagram of a torque load applying state of a circular loading based rotational friction coefficient measurement method according to an embodiment of the present invention;
fig. 11 is a schematic flow chart of a rotational friction coefficient measuring method based on circular loading according to an embodiment of the present invention.
In all the figures, the same reference numerals denote the same features, in particular: the method comprises the following steps of 1-rotary drilling module, 11-rotary drilling rod, 12-drilling machine mast, 13-power unit, 14-rotary drilling bit, 2-annular loading module, 21-connecting end plate, 22-annular loading plate, 23-bolt hole, 3-vertical pressurizing module, 4-vertical pressure measuring module, 41-strain gauge, 5-rotary drilling rod settlement measuring module, 51-laser displacement sensor and 6-torque load measuring module.
Detailed Description
In order to make the objects, 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 with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided in the present invention may be arbitrarily combined with each other to form a feasible technical solution, and the combination is not limited by the sequence of steps and/or the structural composition mode, but must be based on the realization of the capability of a person skilled in the art, and when the technical solution combination is contradictory or cannot be realized, the technical solution combination should be considered to be absent and not to be within the protection scope of the present invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, when an element is referred to as being "fixed to", "disposed on" or "provided on" another element, it may be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element; the terms "mounted," "connected," and "provided" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
As shown in fig. 1-4, one aspect of the present invention provides a rotary friction coefficient measurement system based on annular loading, which is used in cooperation with a rotary drilling rig to measure the surface friction coefficient of a measured holding power layer, and includes a rotary drilling module 1, a hole cleaning module, an annular loading module 2, a vertical pressurizing module 3, a vertical pressure measuring module 4, a rotary drill rod settlement measuring module 5 and a torque load measuring module 6, which are arranged on the rotary drilling module 1; carrying out rotary drilling to a designed elevation or a bedrock position to be detected through the rotary drilling module 1; the vertical pressurizing module 3 is used for applying vertical pressure to the rotary drilling module 1 in a grading manner, the rotary drilling module 1 is used for providing counterforce by means of the gravity of the rotary drilling module 1, the generated vertical pressure is transmitted to the annular loading module 2, the annular loading module 2 is used for applying vertical pressure to a measured rock mass at the lower part to generate settlement, a settlement value generated by the annular loading module 2 under each grade of load condition is monitored in real time through a rotary drilling rod settlement measuring module 5 installed on the rotary drilling module 1, and a vertical pressure value applied by the vertical pressurizing module 3 is measured in real time through a vertical pressure measuring module 4 on the rotary drilling module 1; applying torque load to the annular loading module 2 through a power unit of the rotary drilling module 1, and monitoring a torque value in real time through a torque load measuring module 6 arranged in the power unit; carrying out a plurality of (at least 5 groups of tests) torsional friction tests of the annular loading module under different vertical pressure values, taking the torsional friction tests into a rock mass friction coefficient calculation formula of a rock mass bearing stratum to obtain friction coefficients and calculating an average value, thus obtaining the friction coefficient value of the rock (soil) body of the tested bearing stratum; the method can directly test and obtain the friction coefficient of the rock mass of the bearing stratum in the project investigation stage, and compared with the traditional measuring method, the method has the advantages of low test cost and high safety.
Further, as shown in fig. 1 to 4, the rotary drilling module 1 includes a rotary drilling rod 11, a drilling machine mast 12 connected to the rotary drilling rod 11, a power unit 13 connected to the rotary drilling rod 11 and the drilling machine mast 12, and a rotary drilling bit 14 disposed at the bottom of the rotary drilling rod 11; the rotary drilling module 1 is used for rotary drilling to a designed elevation or a bedrock position to be detected; the rotary drilling rod 11 has enough rigidity and can control the elastic distortion of the rod body during torsion.
Further, as shown in fig. 1-4, the annular loading module 2 is an annular end plate structure that can be mounted at the end of the rotary drilling bit 14, and is a collection of a plurality of annular units 24; the annular loading module 2 comprises a connecting end plate 21 connected with the bottom of the rotary drilling bit 14 and an annular loading plate 22 connected with the connecting end plate 21; the connecting end plate 21 is a round steel plate, and the thickness is not less than 10cm; a plurality of bolt holes 23 are uniformly formed in the circumferential side face of the connecting end plate 21 at intervals and used for installing the connecting end plate 21 to the bottom of the rotary drilling bit 14 in a bolt connection mode; the annular loading plate 22 is a tubular concrete member, and the bottom of the annular loading plate clings to the surface of a tested rock mass bearing layer when the annular loading plate works; the side face of the rotary drilling bit 14 keeps a certain distance with the hole wall, so that the friction of the hole wall on the annular loading module 2 is avoided; the bottom surface fluctuation difference of the annular loading plate 22, the fluctuation difference of the loading surface of the tested rock mass (or rock soil, hereinafter referred to as rock mass) and the number of test groups meet the requirements of engineering rock mass test method standard (GBT 50266-2013) so as to ensure that the annular loading plate 22 is tightly attached to the tested rock mass.
Further, as shown in fig. 1-4, the vertical pressurization module 3 is used for performing graded vertical pressurization on the annular loading module 2; the vertical pressure measuring module 4 is used for measuring the vertical pressure applied to the annular loading module 2 by the vertical pressurizing module 3; the vertical pressure measuring module 4 comprises a plurality of groups of strain gauges 41 arranged on the rotary drilling rod 11; the rotary drilling rod settlement measuring module 5 is used for measuring the settlement value of the rotary drilling rod and is realized by arranging a laser displacement sensor 51 on the mast 12 of the drilling machine; the laser displacement sensor 51 is arranged on the side surface of the bottom end of the mast 12 of the drilling machine and used for monitoring the settlement value of the rotary drilling rod 11 generated by the vertical pressurizing module 3 under the condition of each level of load in real time, and similarly, the settlement value of the annular loading module 2 or the measured rock mass; the vertical pressurizing module 3 is used for applying vertical pressure to the rotary drilling rod 11 in a grading manner, the self gravity of the rotary drilling rod 11 is used for providing counter force, the pressure is transmitted to the annular loading module 2 to apply vertical pressure to a rock body, so that the rotary drilling rod 11 is settled, and a pressure value is kept constant until the settlement value is stable; monitoring a settlement value generated by rotatably digging the drill rod 11 under the condition of each level of load in real time through a laser displacement sensor 51 arranged at the bottom of a mast 12 of the drilling machine; fixing the laser displacement sensor 51 on a mast 12 of the rotary drilling rig, monitoring the settlement of the rotary drilling rod 11 under each level of load when the vertical pressurizing module 3 pressurizes, and when the displacement difference of the rotary drilling rod 11 within 5 minutes under the same level of load condition is not more than 0.01mm, judging that the settlement of the rotary drilling rod 11 reaches the maximum value, and keeping the pressure value constant; the strain gauges 41 are preferably 4 groups, are uniformly arranged on the surface of the rotary drilling rod 11, and each group of strain gauges 41 is located on the same horizontal section of the rotary drilling rod 11 and is used for monitoring the vertical pressure applied to the rotary drilling rod 11 by the vertical pressurization module 3 in real time;
further, as shown in fig. 1 to 4, the torque load measuring module 6 employs a torque sensor, applies a torque load to the measured rock mass in stages through the power unit 13, and monitors a torque load value and a torsion angle output by the torque of each stage of the power unit 13 in real time through the torque sensor arranged in the power unit 13; the torque load value is applied according to the estimated maximum torque value of 8-12 grades, and when the torsion angle caused by applying the torque load is obviously increased, the torsion load grading can be properly increased; in the torque load application process, the vertical pressure is always kept constant; applying the next stage by a time control method every 5 minutes until the torsional slip is suddenly generated, and recording the previous stage torque value T of the sudden torsional slip of the equipment, wherein the torque value T indicates that the slip friction damage is generated; when the rotary drilling rig is close to the friction sliding, the change conditions of the rotation angle and the torque value of the drill rod of the rotary drilling rig are closely concerned.
As shown in fig. 5-11, another aspect of the present invention provides a rotary friction coefficient measuring method based on annular loading, which is used for measuring the rock friction coefficient of a rock mass bearing stratum, and comprises the following steps:
s1: measuring and determining a preset position to be tested and detected, and rotary excavating a drilling module to drill a hole to a designed elevation or a bedrock position to be tested; after the hole is formed, the hole cleaning module cleans the hole to ensure that no sludge exists at the bottom of the hole; measuring and lofting, measuring and determining a preset position to be tested and detected; drilling a hole of the drilling module by a rotary drilling rig to a designed elevation or a bedrock position to be measured; in the drilling process, a steel casing is discharged by a drawing machine to prevent hole collapse, and the steel casing is required to follow to the bottom of a hole; the inner diameter of the steel casing is larger than the outer diameter of the annular loading plate device, so that friction force generated by the side wall on the steel casing is avoided; cleaning holes by the hole cleaning module, cleaning the holes by adopting reverse circulation after a rotary drilling rig drills the holes, cleaning the holes, washing the friction surfaces clean and ensuring that no sludge exists at the bottom of the holes; for the water-containing hole, connecting a conduit on site, and cleaning the hole by adopting a gas lift reverse circulation hole cleaning method;
s2: installing an annular loading module to the bottom of the rotary drilling module in a state that hole cleaning operation is continuously uninterrupted, pulling out a hole cleaning guide pipe after the installation of the annular loading module is completed, and drilling down the rotary drilling bit to a designed elevation position of the hole bottom; the annular loading module is an annular end plate which can be installed at the end part of the rotary drilling bit and comprises a connecting end plate connected with the bottom of the rotary drilling bit and an annular loading plate connected with the connecting end plate; the annular loading plate bottom comprises a plurality of annular units;
s3: installing a vertical pressure measuring module on the rotary drilling rod, applying vertical pressure to the rotary drilling rod in a grading manner through the vertical pressure measuring module and transmitting the vertical pressure to the annular loading module, measuring and obtaining the applied vertical pressure value through the vertical pressure measuring module, measuring and obtaining a settlement value of the rotary drilling rod through the rotary drilling rod settlement measuring module, keeping the output pressure of the vertical pressure measuring module constant after the settlement value of the rotary drilling rod is stable, and removing the vertical pressure measuring module; specifically, multiple groups of strain gauges are adhered to the same horizontal section of the rotary drilling rod, vertical pressure is applied to the rotary drilling rod in a grading mode through a vertical pressurizing module and is transmitted to an annular loading module, a sedimentation value of the rotary drilling rod is read in real time through a laser displacement sensor, the output pressure of the vertical pressurizing module is kept constant after the sedimentation amount of the rotary drilling rod is stable, and the strain gauges are removed; the vertical pressurizing module applies the vertical pressure of the rotary drilling rod in 1-3 levels, a time control method is adopted, a first-level load is applied every 5 minutes, the sedimentation value of the rotary drilling rod after the load is applied is immediately read and measured through a laser displacement sensor after each load application, when the sedimentation value difference of the rotary drilling rod after continuous two times of reading and measurement is not more than 0.01mm, the output pressure of the vertical pressurizing module is kept constant after the sedimentation value of the rotary drilling rod is judged to be stable, and the strain gauge connecting wire is removed;
s4: applying torque loads to the annular loading module in a grading manner through a power unit on the rotary drilling rod until torsional sliding is suddenly generated, and monitoring in real time through a torque load measuring module arranged in the power unit and obtaining a torque value; the torque load is applied according to the estimated maximum torque value of 8-12 grades, and when the torsion angle caused by applying the torque load is obviously increased, the torsion load grading can be properly increased; the torque application method adopts a time control method, applies the torque at one level every 5 minutes until the torque slips suddenly, records the torque value T at the moment, and shows that the slip friction phenomenon occurs under the torque value T; when the rotary drilling rod is close to the friction sliding, the change conditions of the rotation angle and the torque value of the rotary drilling rod are closely concerned;
s5: repeatedly carrying out multiple single-point annular loading module torsional friction coefficient test tests under different vertical pressures according to the steps S3 and S4, substituting the test results into a rock mass friction coefficient calculation formula of a rock mass bearing layer to obtain friction coefficients and calculating an average value to obtain the value of the friction coefficient of the rock mass of the tested bearing layer; repeatedly carrying out no less than 5 single-point repeated friction coefficient test tests under different vertical pressures according to the steps S3 and S4, and taking the average value as the friction coefficient measurement result of the measurement point if the extreme values of a plurality of groups of test data are not more than 30% of the average value; when the annular loading module rotates at a certain speed, the annular loading module generates torque due to the action of base friction force, and the torque generated by different vertical pressures is different;
the loading stable output torque value T of the annular loading module is calculated by the formula (1):
wherein the content of the first and second substances,
the area of an annular unit at the bottom of the annular loading plate is shown;
shearing stress for the annular unit substrate;
the distance from the annular unit to the central axis of the annular loading plate;
is the annular load plate area;
is the sign of the integral;
annular load plate bottom annular cell area
Equal to the product of the annular circumference of the annular element and the radial width of the annular element, calculated by equation (2):
wherein the content of the first and second substances,
the area of an annular unit at the bottom of the annular loading plate is shown;
representing the width of the ring-shaped element;
the distance from the annular unit to the central axis of the annular loading plate;
is the inner diameter of the annular loading plate;
annular cell base undercut stress
Equal to normal stress and friction coefficientThe product, calculated by equation (3):
wherein the content of the first and second substances,
the coefficient of friction of the rock mass in the rock mass bearing layer;
the vertical pressure value borne by the annular loading module is obtained;
the annular load plate area;
as can be seen from the formulas (1) and (3), the loading of the annular loading module stabilizes the output torque value
Can also be represented by formula (4):
wherein:
the annular load plate area;
the coefficient of friction of the rock mass in the rock mass bearing layer;
the vertical pressure value borne by the annular loading module is obtained;
is the outer diameter of the annular loading plate;
is the inner diameter of the annular loading plate;
is the sign of the integral;
annular load plate area
Represented by formula (5):
wherein, the first and the second end of the pipe are connected with each other,
，
is the outer diameter of the annular loading plate,
the inner diameter of the annular loading plate is a known quantity;
as can be seen from the equations (4) and (5), the coefficient of friction of the rock mass in the rock mass bearing stratum
Calculated by equation (6):
wherein the content of the first and second substances,
is the friction coefficient of the rock mass of the body bearing stratum;
is a ringThe loading stable output torque value of the shape loading module;
the vertical pressure value borne by the annular loading module is obtained;
is the outer diameter of the annular loading plate;
is the inner diameter of the annular loading plate;
in conclusion, the rock mass friction coefficient of the rock mass bearing layer at the bottom of the annular loading module can be obtained through calculation 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 borne by the annular loading module, the outer diameter D of the annular loading plate and the inner diameter D of the annular loading plate; the annular loading module can measure different rotation torque values due to different vertical pressures, the measured friction coefficient is a fixed value, and the average friction coefficient value, namely the matrix friction coefficient value, of the friction coefficient average value is obtained by carrying out multiple (at least 5 groups of tests) torsional friction tests of the annular loading module under different vertical pressure values.
The invention relates to a rock mass friction coefficient testing system and method of a rock mass holding layer based on an annular loading rotary friction coefficient measuring system, which has the working principle that: carrying out rotary drilling to a designed elevation or a bedrock position to be detected through the rotary drilling module 1; the vertical pressurizing module 3 is used for applying vertical pressure to the rotary drilling module 1 in a grading manner, the self gravity of the rotary drilling module 1 is used for providing counter force, the generated vertical pressure is transmitted to the annular loading module 2 through the power unit 13, the rotary drilling rod 11 and the rotary drilling bit 14, the annular loading module 2 is used for applying vertical pressure to a lower measured rock body to generate settlement, a settlement value generated by the rotary drilling rod 11 under each grade of load condition is monitored in real time through a laser displacement sensor 51 arranged at the bottom of a mast 12 of the drilling machine, and a vertical pressure value applied by the vertical pressurizing module is measured through a strain gauge 41 on the rotary drilling rod; applying torque load to the annular loading module 2 through the power unit 13 on the rotary drilling rod 11, and monitoring a torque value in real time through a torque sensor arranged in the power unit 13; carrying out a plurality of (at least 5 groups of tests) torsional friction tests of the annular loading module under different vertical pressure values, taking the torsional friction tests into a rock mass friction coefficient calculation formula of a rock mass bearing stratum to obtain friction coefficients and calculating an average value, thus obtaining the friction coefficient value of the rock (soil) body of the tested bearing stratum; the rotary friction coefficient measuring system and method based on annular loading are 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 operation environment, a reverse circulation drilling machine is adopted to cut the bottom of a drilled hole in a rotary mode to be flat, a drill bit with an annular loading plate rotary friction device is replaced, and then loading friction testing is carried out on the bearing layer; if the water level is buried in a deeper dry working environment, after the hole forming is completed, the steel casing is followed to the bottom, and the test surface is manually processed to meet the flatness and the fluctuation difference required by the test; the method can directly test and obtain the friction coefficient of the rock mass of the bearing stratum in the project investigation stage, and compared with the traditional measuring method, the method has the advantages of low test cost and high safety.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A rotary friction coefficient measuring method based on annular loading is characterized by comprising the following steps:
s1: measuring and determining a detection position to be tested, and rotary excavating a drilling module to drill a hole to a designed elevation or a bedrock position to be tested; after hole forming, the hole cleaning module cleans holes to ensure that no sludge exists at the bottom of the holes;
s2: under the continuous uninterrupted state of hole cleaning operation, mounting an annular loading module to the bottom of the rotary drilling module, after the annular loading module is mounted, pulling out the hole cleaning guide pipe, and lowering a rotary drilling bit to sink the annular loading module to the surface of the bedrock to be detected at the bottom of the hole;
s3: installing a vertical pressure measuring module on the rotary drilling rod, applying vertical pressure to the annular loading module in a grading manner through the vertical pressurizing module, measuring the applied vertical pressure value through the vertical pressure measuring module, measuring the settlement value of the rotary drilling rod through the rotary drilling rod settlement measuring module, keeping the output pressure of the vertical pressurizing module constant after the settlement of the rotary drilling rod is stable, and removing the vertical pressure measuring module;
s4: applying torque loads to the annular loading module in a grading manner through a power unit on the rotary drilling rod, and monitoring and obtaining a torque value through a torque load measuring module arranged in the power unit when torsional slip is suddenly generated;
s5: repeatedly carrying out multiple single-point annular loading module torsional friction coefficient test tests under different vertical pressures according to the steps S3 and S4, substituting the test tests into a rock mass friction coefficient calculation formula of the rock mass bearing layer to obtain a friction coefficient and calculating an average value to obtain a rock mass friction coefficient value of the tested rock mass bearing layer;
step S5, the friction coefficient of rock mass in rock mass supporting layer
Calculated by the following formula:
wherein, the first and the second end of the pipe are connected with each other,
the coefficient of friction of the rock mass in the rock mass bearing layer; t is a loading stable output torque value of the annular loading module; n is a vertical pressure value borne by the annular loading module; d is the outer diameter of the annular loading plate; d is the inner diameter of the annular loading plate.
2. The method for determining the rotary friction coefficient based on the annular loading according to claim 1, wherein the step S3 further comprises the steps of applying vertical pressure to the rotary drilling rod by the vertical pressurizing module in 1-3 levels, applying a first-level load every 5 minutes, immediately reading the sedimentation value of the rotary drilling rod after the loading by the rotary drilling rod sedimentation value measuring module after each load application, and judging that the sedimentation value of the rotary drilling rod is stable when the difference between the sedimentation values of the rotary drilling rod measured and read continuously twice is not more than 0.01 mm.
3. The method of claim 2, wherein the step S4 further comprises: applying the torque load according to 8-12 grades of estimated maximum torque values, and increasing the grade of the torsional load when the torsional angle caused by applying the torque load is obviously increased; the torque load application method adopts a time control method and applies the torque load to the first stage every 5 minutes of stability.
4. The rotary friction coefficient measuring system based on annular loading is characterized by being used for realizing the rotary friction coefficient measuring method based on annular loading according to any one of claims 1 to 3, and comprising a rotary drilling module (1), an annular loading module (2), a vertical pressurizing module (3), a vertical pressure measuring module (4), a rotary drilling rod settlement measuring module (5) and a torque load measuring module (6) which are arranged on the rotary drilling module (1); wherein the content of the first and second substances,
the torque load measuring module (6) is arranged in a power unit of the rotary drilling module (1); the vertical pressurizing module (3) is used for applying vertical pressure to the rotary drilling module (1) in a grading manner, the self gravity of the rotary drilling module (1) is used for providing counter force, the generated vertical pressure is transmitted to the annular loading module (2), the annular loading module (2) is used for applying vertical pressure to a rock mass to be measured at the lower part to generate settlement, a settlement value generated by the annular loading module (2) under each grade of load condition is monitored in real time through a rotary drilling rod settlement measuring module (5) installed on the rotary drilling module (1), and a vertical pressure value applied by the vertical pressurizing module (3) is measured in real time through a vertical pressure measuring module (4) installed on the rotary drilling module (1); applying torque load to the annular loading module (2) through a power unit of the rotary drilling module (1), and monitoring a torque value in real time through a torque load measuring module (6) arranged in the power unit; through carrying out annular loading module torsional friction test under the different vertical pressure value many times, substitute rock mass holding layer rock mass coefficient of friction calculation formula and ask coefficient of friction and calculate the average value, obtain the rock mass holding layer rock mass coefficient of friction value of being surveyed.
5. The annular loading-based rotary friction coefficient measuring system according to claim 4, wherein the rotary drilling module (1) comprises a rotary drilling rod (11), a drilling machine mast (12) connected with the rotary drilling rod (11), a power unit (13) connected with the rotary drilling rod (11) and the drilling machine mast (12) at the same time, and a rotary drilling bit (14) arranged at the bottom of the rotary drilling rod (11).
6. The rotary friction coefficient measuring system based on annular loading according to claim 5, characterized in that the annular loading module (2) comprises a connecting end plate (21) connected with the bottom of the rotary drilling bit (14) and an annular loading plate (22) connected with the connecting end plate (21);
the connecting end plate (21) is a circular plate, and the thickness of the connecting end plate is not less than 10cm;
a plurality of bolt holes (23) for mounting the connecting end plate (21) to the bottom of the rotary drilling bit (14) are uniformly arranged on the circumferential side surface of the connecting end plate (21) at intervals;
the annular loading plate (22) is a tubular concrete member;
the bottom surface of the annular loading plate (22) can be tightly attached to the rock mass to be measured.
7. The annular loading-based rotary friction coefficient measuring system according to claim 6, wherein the vertical pressure measuring module (4) comprises a plurality of groups of strain gauges (41) arranged on the rotary drilling rod (11);
the rotary drilling rod settlement measuring module (5) is realized by arranging a laser displacement sensor (51) on the drilling machine mast (12).
8. The circular loading-based rotary friction coefficient measuring system according to claim 7, wherein the laser displacement sensor (51) is arranged at the bottom end side of the mast (12) of the drilling machine, and is used for monitoring the sedimentation value of the rotary drilling rod (11) generated by the vertical pressurizing module (3) under each stage of load condition in real time;
the strain gauges (41) are uniformly arranged on the surface of the rotary drilling rod (11), and each group of strain gauges (41) are located on the same horizontal section of the rotary drilling rod (11).
9. A toroidal loading based rotary system as claimed in claim 8, wherein said torque load measuring module (6) employs torque sensors for real time monitoring of torque load value and torque angle of each stage of torque output of said power unit (13);
applying the torque load value in 8-12 grades according to the estimated maximum torque value, and increasing the grade of the torsional load when the torsional angle caused by applying the torque load is obviously increased;
the torque load Shi Jiaan applied the next stage every 5 minutes of stabilization, when a sudden torsional slip occurred, the previous stage torque value at which the sudden torsional slip occurred was recorded.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211140441.2A CN115217166B (en) | 2022-09-20 | 2022-09-20 | Rotary friction coefficient measuring method and system based on annular loading |
| PCT/CN2022/131578 WO2024060380A1 (en) | 2022-09-20 | 2022-11-13 | Rotary friction coefficient measurement method and system based on annular loading |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211140441.2A CN115217166B (en) | 2022-09-20 | 2022-09-20 | Rotary friction coefficient measuring method and system based on annular loading |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115217166A CN115217166A (en) | 2022-10-21 |
| CN115217166B true CN115217166B (en) | 2022-12-09 |
Family
ID=83617256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211140441.2A Active CN115217166B (en) | 2022-09-20 | 2022-09-20 | Rotary friction coefficient measuring method and system based on annular loading |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN115217166B (en) |
| WO (1) | WO2024060380A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115217166B (en) * | 2022-09-20 | 2022-12-09 | 中交公路长大桥建设国家工程研究中心有限公司 | Rotary friction coefficient measuring method and system based on annular loading |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4760735A (en) * | 1986-10-07 | 1988-08-02 | Anadrill, Inc. | Method and apparatus for investigating drag and torque loss in the drilling process |
| CN110579438A (en) * | 2019-10-08 | 2019-12-17 | 长安大学 | Dynamic shear rheometer friction coefficient testing device and using method |
| CN112014009A (en) * | 2020-08-28 | 2020-12-01 | 徐州徐工基础工程机械有限公司 | Rotary drilling rig torque and pressure load spectrum testing method |
| CN113218646A (en) * | 2021-05-14 | 2021-08-06 | 徐州徐工基础工程机械有限公司 | Drill rod load testing method for rotary drilling rig |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6153911A (en) * | 1984-08-23 | 1986-03-18 | Toa Harbor Works Co Ltd | Device of measuring peripheral surface friction force of pile |
| CN104345028A (en) * | 2014-10-14 | 2015-02-11 | 中山大学 | Pile soil sliding friction testing method |
| KR102236250B1 (en) * | 2019-08-28 | 2021-04-02 | 김채민 | Calculation method of side resistenace load and Calculation method of side resistenance load of each stratum |
| GB2614646A (en) * | 2020-09-16 | 2023-07-12 | Baker Hughes Oilfield Operations Llc | System to model distributed torque, drag and friction along a string |
| JP7348157B2 (en) * | 2020-11-30 | 2023-09-20 | 大成建設株式会社 | Friction coefficient measuring device and friction coefficient measuring method |
| CN114965251A (en) * | 2022-05-07 | 2022-08-30 | 广西欣港交通投资有限公司 | Self-balancing concrete and rock friction coefficient measuring system and testing method |
| CN115217166B (en) * | 2022-09-20 | 2022-12-09 | 中交公路长大桥建设国家工程研究中心有限公司 | Rotary friction coefficient measuring method and system based on annular loading |
-
2022
- 2022-09-20 CN CN202211140441.2A patent/CN115217166B/en active Active
- 2022-11-13 WO PCT/CN2022/131578 patent/WO2024060380A1/en unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4760735A (en) * | 1986-10-07 | 1988-08-02 | Anadrill, Inc. | Method and apparatus for investigating drag and torque loss in the drilling process |
| CN110579438A (en) * | 2019-10-08 | 2019-12-17 | 长安大学 | Dynamic shear rheometer friction coefficient testing device and using method |
| CN112014009A (en) * | 2020-08-28 | 2020-12-01 | 徐州徐工基础工程机械有限公司 | Rotary drilling rig torque and pressure load spectrum testing method |
| CN113218646A (en) * | 2021-05-14 | 2021-08-06 | 徐州徐工基础工程机械有限公司 | Drill rod load testing method for rotary drilling rig |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2024060380A1 (en) | 2024-03-28 |
| CN115217166A (en) | 2022-10-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Spagnoli et al. | A review on the behavior of helical piles as a potential offshore foundation system | |
| Jardine et al. | Studies of the influence of non-linear stress–strain characteristics in soil–structure interaction | |
| Paik et al. | Determination of bearing capacity of open-ended piles in sand | |
| Paik et al. | Behavior of open-and closed-ended piles driven into sands | |
| Sakr | Installation and performance characteristics of high capacity helical piles in cohesionless soils | |
| EP0386810A2 (en) | Method for improving a drilling process by characterizing the hydraulics of the drilling system | |
| RU2582896C2 (en) | Testing stiffness based on acoustic emission with low noise coefficients | |
| ASTM Subcommittee 18.02 | Suggested method for performing the flat dilatometer test | |
| EP0154261B1 (en) | Method and apparatus for testing soil | |
| RU2550314C2 (en) | Testing of rigidity based on acoustic emission for pdc, pcbn or other hard or superhard materials | |
| CN115217166B (en) | Rotary friction coefficient measuring method and system based on annular loading | |
| US20200278473A1 (en) | Borehole inspecting and testing device and method of using the same | |
| WO2010080993A2 (en) | Sensor, methods of calibrating a sensor, methods of operating a sensor | |
| US5109702A (en) | Method for determining liquefaction potential of cohesionless soils | |
| Lutenegger | Screw piles and helical anchors–what we know and what we don’t know: an academic perspective–2019 | |
| CN114577635A (en) | Surface rock embodiment shear test device and test method | |
| Harnish | Helical pile installation torque and capacity correlations | |
| Schneider et al. | Apparatus for measuring pipe-soil interaction behavior using shallow ‘pipe-like’penetrometers | |
| JP3803922B2 (en) | In-situ liquefaction and dynamic characteristics testing method and testing equipment using boreholes | |
| Chung | Characterisation of soft soils for deep water developments | |
| CN113532544B (en) | Real-time testing device for strain stiffness and stress state of soil body and construction testing method thereof | |
| Annicchini et al. | Effects of installation advancement rate on helical pile helix behavior in very dense sand | |
| Masterson et al. | Strain measurements in floating ice platforms and their application to platform design | |
| Zuidberg et al. | EURIPIDES, load tests on large driven piles in dense silica sands | |
| King et al. | The influence of rate of loading on the behaviour of continuous-flight-auger bored piles in soft clay |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |