WO1986006830A1 - Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation - Google Patents

Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation Download PDF

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Publication number
WO1986006830A1
WO1986006830A1 PCT/US1985/000863 US8500863W WO8606830A1 WO 1986006830 A1 WO1986006830 A1 WO 1986006830A1 US 8500863 W US8500863 W US 8500863W WO 8606830 A1 WO8606830 A1 WO 8606830A1
Authority
WO
WIPO (PCT)
Prior art keywords
hollow body
stress
gage
meter
gage plug
Prior art date
Application number
PCT/US1985/000863
Other languages
English (en)
Inventor
Duk-Won Park
Theodore W. Ryan
Original Assignee
University Of Alabama
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by University Of Alabama filed Critical University Of Alabama
Priority to PCT/US1985/000863 priority Critical patent/WO1986006830A1/fr
Priority to EP19850902783 priority patent/EP0232248A1/fr
Publication of WO1986006830A1 publication Critical patent/WO1986006830A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
    • E21B49/006—Measuring wall stresses in the borehole

Definitions

  • the present invention is directed to a atress- meter for measuring stress in earth material such as rock or soil.
  • the invention is further directed to a method and apparatus for installing the stress-meter.
  • the gage plug upon which strain gages can be fixed.
  • the gage plug has a tapered outer surface and is insertable within a hollow body having a similar tapered configuration.
  • the size of the gage plug is such that it can freely fit in one end of the hollow body but, at some point along its length, contacts the tapered inner surface of the hollow body so that further movement of the gage plug creates radial stresses in the hollow body and gage plug.
  • the hollow body itself is constructed so that it can resiliently expand in the radial direction.
  • the hollow body is a cylindrical pipe having axial slots.
  • the hollow body is a shell having circumferentially spaced portions, some of which are connected via springs.
  • a setting device for inserting the hollow body within the borehole.
  • This device can be in the form of one or more pipes which are axially releasably connected. One end of one of these pipes includes releasable connections for the hollow body.
  • the hollow body can be inserted into a borehole for a large distance by use of several connected lengths of the pipe.
  • the insertion device can be in the form of a setting head having a spring stabilized releasable connection to the hollow body.
  • the hollow body having the gage plug loosely positioned therein one can prestress the gage plug and strain gages thereon by advancing the gage plug into the hollow body until the tapered gage plug begins to resiliently radially expand the hollow body.
  • This advancement of the gage plug is accomplished by either a mechanical or hydraulic element which is advanced through the hollow body setting pipe or the setting head.
  • the gage plug can be advanced by a second pipe which is longer than the setting pipe and which is slidable therein.
  • the second pipe can be advanced manually or with the aid of a hydraulic jack.
  • the gage plug is advanced by a piston slidable therein.
  • the piston can be either manually or hydraulically advanced. After the installation and prestressing of the gage plug within the hollow body, the setting device is removed at the releasable connection.
  • the strain gages are connected to a device for measuring and processing the strain detected by the strain gages before or during the setting steps.
  • the strain gages can be set for either measuring plane stress or uniaxial stress.
  • FIGURE 1 is an orthogonal view of a first embo iment of the gage plug upon which the strain gages are fixed for plane stress measurement;
  • FIGURE 1A is a variant of the embodiment of FIGURE 2;
  • FIGURE 2 is an orthogonal view of a second embodiment of the gage plug upon which strain gages are fixed for uniaxial stress measurement;
  • FIGURE 2A is a variant of the embodiment of FIGURE 2;
  • FIGURE 3 is a side view of the gage plug of FIGURES 1 or 2, showing the tapered surface of the gage plug;
  • FIGURE 4 is an orthogonal view of a first embodiment of the hollow body within which the gage plug is inserted;
  • FIGURE 5 is a side view of the hollow body of FIGURE 4.
  • FIGURE 6 is an orthogonal view showing a device for installing or setting the hollow body of FIGURES 4 and 5 within a borehole and for manually advancing the gage plug within the hollow body;
  • FIGURE 7 is an orthogonal view of a second embodiment of the hollow body
  • FIGURE 8 is an orthogonal view of a variant of the embodiment of FIGURE 7;
  • FIGURE 9 shows a hydraulic device for advancing the gage plug within the hollow body
  • FIGURE 10 is a sectional view of a second embodiment of a device for setting the hollow body within a borehole.
  • FIGURE 11 is a sectional view showing a variant of the embodiment of FIGURE 10.
  • strain gages 2 are rigidly adhesively bonded onto axial end surfaces 4 and 6 of gage plug 8 or 8'.
  • the tapered cylindrical gage plug of FIGURE 1 is used whereas when measuring uniaxial stress only a portion of the plug is cylindrical and side surfaces of the cylinder are flattened, as seen in FIGURE 2.
  • the gage plug is formed of metal, plexiglass or other composite material, depending upon the desired stress response characteristics.
  • strain gages 2 mounted for strain measurement along two mutually perpendicular directions, or three strain gages (2') mounted in triangular pattern, are bonded to each end surface of the gage plug 8 or 8'.
  • uniaxial stress as seen in FIGURES 2 and 2A, only a single strain gage 2 or 2" need be provided on each end surface or on each side, each strain gage being oriented for strain measurement along the same direction 20.
  • leads can be attached to each of the strain gages.
  • the leads provide electrical signals to a device for processing the signals from the strain gages and calculating the stress from which the strain being measured was derived.
  • a signal processing device is the Strain Indicator model P-3500 or P-350A manufactured by Instruments Division, Measurement Group Incorporated of Raleigh, North Carolina.
  • FIGURES 4 and 5 A first embodiment of such a hollow body is seen in FIGURES 4 and 5.
  • the hollow body of this embodiment is in the form of a cylinder.10.
  • the cylinder can be formed of metal or plastic, again depending upon the stress response characteristics desired.
  • the cylinder 10 has a tapered conical inner surface 12 whose diameter grows progressively smaller toward the end 14. The taper can range from between 1 and 5°, and corresponds in slope to the taper of the peripheral surface of 16 of the gage plug, as best seen in FIGURE 3.
  • the gage plug is sized so that it can freely fit in the larger end 18 of the cylinder 10 but, at some point along the length of the cylinder 10, the tapered surface 16 of the gage plug fits snugly against the correspondingly shaped tapered inner surface 12 of the cylinder 10. At this point, any further movement of the gage plug toward end 14 of the cylinder 10 will radially stress both the gage plug and the cylinder. In the case of the gage plug of FIGURE 1, the stress will be applied about the entire circumference of the gage plug so that plane stress can be measured.
  • the wall of the cylinder 10 has a circumferentially spaced array of slots 22 extending entirely therethrough in the radially direction.
  • Each of the slots begins at one axial end of the cylinder and terminates at a point along the length of the cylinder. Alternating slots originate at opposite ends 14 or 18 of the cylinder 10 so that the cylinder can radially expand or contract in an even manner.
  • Each of the slots terminates in an enlarged portion 24 in order to avoid the development of stress concentrations at the ends of the slots.
  • the gage plug 8 or-8' is advanced into the cylinder 10 from end 18 toward end 14, at some point along the length of the cylinder the gage plug will snugly fit against the tapered surface 12 of the cylinder.
  • the gage plug 8 which has a circular section identical to that of the cylinder 10
  • the gage plug will fit snugly against the surface 12 about its entire periphery.
  • the gage plug 8 1 whose sides are straight, only the curved periphery adjacent the direction 20 will conform to the shape of the surface 12 and fit thereagainst. Further movement of the gage plug toward the end 14 of the cylinder will cause axial expansion of the cylinder 10, by expanding the slots 22 until snug contact with rock walls of the borehole is achieved, and the resilience of the material of the cylinder will result in a compressive prestressing of the gage plug.
  • FIGURES 7 and 8 A second embodiment of the hollow body is seen in FIGURES 7 and 8.
  • the expandable hollow body 10 • is formed of circumferentially opposing first portions 30 and 31 and circumferentially opposing second or side portions 32.
  • the first portions 30 and 31 have a cylindrical outer configuration while the second portions 32 have flat outer sides.
  • the first portion 31 is welded to the sides 32 while the other first portion 30 includes lugs 34 which fit in slots of the second portions 32 for maintaining the relative positions of the first portion 30 relative to the second portions 32.
  • the first portion 30 and the second portions are biased apart so as to create expansion in the radial direction by springs positioned between each of the second portions and the first portion 30.
  • the springs 36 are curved whereas in the embodiment of FIGURE 8 the springs 38 are straight.
  • a sufficient number of lugs 34 are provided to maintain the relative positioning of the elements.
  • the first and second portions define an interior bore whose sectional area is tapered so as to progressively decrease from the left to the right in FIGURES 7 and 8. If the embodiment of FIGURES 7 and 8 is used, the shape of the gage plugs will, of course, be modified so as to conform to the shape of the tapered hollow defined by the expandable hollow body 10".
  • the setting tool is formed from one or more first pipes 40.
  • One of the first pipes 40a is connected directly to the expandable hollow body 10 or 10' by use of releasable connectors.
  • the releasable connectors can, for example, be in the form of a bayonet joint or twistlock joint provided by lugs 42 on one end of the first pipe 40a and corresponding slots or notches 44 (see FIGURES 4 and 5) on the end 18 of the hollow body 10 or on one end of the first portions 30 in FIGURES 7 and 8.
  • the first pipe 40a is twist-locked onto the hollow body and the hollow body is inserted into a bore via this first pipe. If the hollow body must be inserted far into a bore, a threaded connection 46 can be provided between the first pipe 40a and additional first pipes 40b.
  • the following procedure can be followed.
  • the borehole is drilled in the earth material, the borehole having a slightly larger " diameter than that of the hollow body 10 or 10' (0.05 inches to 0.3 inches larger than the diameter of the hollow body, depending upon the taper angle) .
  • the gage plug 8 or 8' is then inserted in the larger end of the hollow defined by the hollow body.
  • the pipe 40a is connected to the hollow body via the lugs 42 and the notches 44.
  • the hollow body is then inserted into the borehole and situated at the proper depth, while allowing the lead wires from the strain gages to be threaded through the slots of the hollow body 10 or between the adjacent portions of the hollow body 10' of FIGURES 7 and 8. Additional pipes are used if necessary. it then becomes necessary to advance the gage plug to the right (as seen in the FIGURES) within the hollow body, so as to prestress the gage plug, as described above.
  • this can be accomplished by providing a plunger in the form of a second pipe 50.
  • the second pipe 50 has a length greater than the sum of all of the first pipes 40a and 40b, and has a smaller diameter, so that it can slide within the first pipes.
  • the pipe 50 is therefore inserted into the first pipes with the end 52 thereof extending out of the first pipes and the opposite end of the pipe 50 contacting the gage plug 8 or 8".
  • a ring 54 may be clamped to the exterior of the first pipes 40 to prevent them from advancing further into the bore of the earth material.
  • the strain gages which have been connected to a strain indicator (not shown), will then provide an indication of prestress.
  • a thin metal lining c-an be wrapped around the hollow body in order to reduce the gap between the borehole in the earth material and the hollow body. It may become necessary to provide a large amount of prestress. Under those circumstances, one may use the hydraulic apparatus shown in FIGURE 9. As can there be seen, a hydraulic cylinder 60 can be posi ⁇ tioned behind the second pipe 50.
  • Connector arms 62 pivoted to the hydraulic cylinder can be moved to the position shown in FIGURE 9 to engage the ring 54 so that the cooperation between the arms 62 and the ring 54 prevents movement of the hydraulic cylinder to the left, while the piston 64 of the hydraulic cylinder is pressed against the end 52 of the second pipe 50 to prevent movement of the cylinder to the right.
  • the hydraulic jack 66 can be actuated so as to provide hydraulic fluid to the cylinder 60 via the lines 68, thereby causing the piston 64 to advance to the right, and so advance both the second pipe 50 and the gage plug 8 or 8 ' for prestressing of the gage plug.
  • the first pipes 40 can be disconnected from the hollow body 10 or 10' and stress can be measured on the strain indicator which has been connected to the strain gages.
  • FIGURES 10 and 11 An alternative setting device is shown in FIGURES 10 and 11.
  • a setting head 70 is provided with an external ring 72 and is releasably connected to a hollow body via a twist-lock or bayonet connection.
  • the setting head is shown connected to the first portions 30 of the hollow body 10' of FIGURE 7 via lugs 74 on the first portions 30 and notches, similar to the notches 44, provided on the end of the setting head.
  • the setting head could also be attached to the hollow body 10 of FIGURES 4 and 5 if the notches 44 are replaced by- lugs 74.
  • a stabilizing spring 76 engaged between the ring 72 and the end of the hollow body maintains the relative positions between the setting head 70 and the hollow body.
  • a plunger in the form of a piston 78 is slidable within the setting head and terminates in a piston head 80 which can engage the gage plug " .
  • the piston can be advanced either manually or via a hydraulic jack such as that of FIGURE 9.
  • the setting head 70 defines a hydraulic cylinder 82 supplied with hydraulic fluid via line 84.
  • a piston 86 which is biased into a retracted position by a spring 88.
  • the hydraulic fluid is applied via the line 84 and advances the piston 86 so that it contacts and advances the gage plug.
  • the spring 88 causes the piston 86 to retract.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Geology (AREA)
  • Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Civil Engineering (AREA)
  • Paleontology (AREA)
  • Soil Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

Un dispositif de mesure de contraintes dans un trou de forage comprend un corps creux pouvant se dilater radialement de manière élastique (10), à l'intérieur duquel peut être positionné un bouchon calibre (8) sur lequel sont fixées des jauges de contraintes. La section interne du corps creux est conique, de même que le bouchon calibre, de sorte que l'avance du bouchon calibre à l'intérieur du corps creux provoque la précontrainte dudit bouchon calibre. Le corps creux peut être introduit dans un forage percé dans la roche ou dans le sol, dont on désire mesurer les contraintes, à l'aide d'un outil d'installation ou de montage. Par la suite, le bouchon calibre est avancé jusqu'au corps creux de manière à soumettre le bouchon calibre à une précontrainte. L'outil de montage est alors enlevé et les contraintes peuvent être mesurées à l'aide d'un indicateur de contraintes approprié.
PCT/US1985/000863 1985-05-13 1985-05-13 Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation WO1986006830A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/US1985/000863 WO1986006830A1 (fr) 1985-05-13 1985-05-13 Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation
EP19850902783 EP0232248A1 (fr) 1985-05-13 1985-05-13 Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1985/000863 WO1986006830A1 (fr) 1985-05-13 1985-05-13 Dispositif de mesure de contraintes dans un trou de forage et procede et appareil en permettant l'installation

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WO1986006830A1 true WO1986006830A1 (fr) 1986-11-20

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0344926A1 (fr) * 1988-05-06 1989-12-06 Eti Explosives Appareil pour contrôler des contraintes de matériaux
DE4129562A1 (de) * 1991-09-03 1993-03-11 Zentralinstitut Fuer Physik De Bohrlochstrainmeter
CN116295076A (zh) * 2023-02-13 2023-06-23 长江水利委员会长江科学院 用于串联式多点位移测量计的安装导向及锁定装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2927459A (en) * 1957-07-18 1960-03-08 Jersey Prod Res Co Measurement of subsurface stress
FR1355579A (fr) * 1962-12-28 1964-03-20 Ct Ex De Rech S Et D Etudes Du Cellule de mesure de déformation de sols à chemisage de positionnement
US3483745A (en) * 1963-12-23 1969-12-16 Patrick Harrison Inc Borehole extensometer
US3557886A (en) * 1969-06-30 1971-01-26 Fenix & Scisson Inc Method and apparatus for measuring in situ the earth stress at a preselected subterranean area
US4159641A (en) * 1974-09-03 1979-07-03 The United States Of America As Represented By The Secretary Of The Interior Vibrating wire stress meter

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2927459A (en) * 1957-07-18 1960-03-08 Jersey Prod Res Co Measurement of subsurface stress
FR1355579A (fr) * 1962-12-28 1964-03-20 Ct Ex De Rech S Et D Etudes Du Cellule de mesure de déformation de sols à chemisage de positionnement
US3349610A (en) * 1962-12-28 1967-10-31 Ct Ex De Rech S Et D Etudes Du Soil deformation measuring cell with positioning liner
US3483745A (en) * 1963-12-23 1969-12-16 Patrick Harrison Inc Borehole extensometer
US3557886A (en) * 1969-06-30 1971-01-26 Fenix & Scisson Inc Method and apparatus for measuring in situ the earth stress at a preselected subterranean area
US4159641A (en) * 1974-09-03 1979-07-03 The United States Of America As Represented By The Secretary Of The Interior Vibrating wire stress meter

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0344926A1 (fr) * 1988-05-06 1989-12-06 Eti Explosives Appareil pour contrôler des contraintes de matériaux
US4962668A (en) * 1988-05-06 1990-10-16 Preston Christoper J Material stress monitor
DE4129562A1 (de) * 1991-09-03 1993-03-11 Zentralinstitut Fuer Physik De Bohrlochstrainmeter
CN116295076A (zh) * 2023-02-13 2023-06-23 长江水利委员会长江科学院 用于串联式多点位移测量计的安装导向及锁定装置
CN116295076B (zh) * 2023-02-13 2024-03-26 长江水利委员会长江科学院 用于串联式多点位移测量计的安装导向及锁定装置

Also Published As

Publication number Publication date
EP0232248A1 (fr) 1987-08-19

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