CN112729632A - Hollow bag strain gauge for preventing cementing agent from overflowing without pressure - Google Patents
Hollow bag strain gauge for preventing cementing agent from overflowing without pressure Download PDFInfo
- Publication number
- CN112729632A CN112729632A CN202110119310.5A CN202110119310A CN112729632A CN 112729632 A CN112729632 A CN 112729632A CN 202110119310 A CN202110119310 A CN 202110119310A CN 112729632 A CN112729632 A CN 112729632A
- Authority
- CN
- China
- Prior art keywords
- cementing agent
- guide head
- strain gauge
- rear end
- mounting column
- 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.)
- Pending
Links
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 67
- 238000007789 sealing Methods 0.000 claims abstract description 22
- 238000009434 installation Methods 0.000 claims abstract description 20
- 238000001125 extrusion Methods 0.000 claims abstract description 17
- 230000000903 blocking effect Effects 0.000 claims description 8
- 239000011230 binding agent Substances 0.000 claims 1
- 239000011435 rock Substances 0.000 abstract description 26
- 238000005259 measurement Methods 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
-
- 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
- E21B23/00—Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells
- E21B23/01—Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells for anchoring the tools or the like
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
- G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
Landscapes
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- General Physics & Mathematics (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
- Piles And Underground Anchors (AREA)
Abstract
A hollow bag strain gauge for preventing a cementing agent from overflowing without pressure comprises a guide head, an installation column, a direction finder and a strain gauge, wherein a cylindrical hole with an open front end is formed in the installation column, the cylindrical hole is filled with the cementing agent, the rear end part of the guide head extends into the front end opening of the cylindrical hole, a sealing ring in sliding sealing fit with the inner wall of the cylindrical hole is arranged on the outer circle of the rear end of the guide head, a positioning structure is arranged between the outer circle of the rear end of the guide head and the installation column, a cementing agent extrusion channel with an open rear end is formed in the guide head, and an elastic one-way valve is arranged in the cementing agent extrusion channel; the outer circumference of the mounting column is provided with a strain gauge and a positioning sleeve for fixing the strain gauge, the direction finder is coaxially mounted inside the rear side of the mounting column, and the rear end of the direction finder is connected with a cable which is connected with the strain gauge simultaneously. The invention solves the problem of the outflow of the cementing agent in advance when measuring the initial stress of the rock mass, and ensures the orderly measurement process and the accuracy of the measurement result.
Description
Technical Field
The invention belongs to the technical field of ground stress measurement, and particularly relates to a hollow inclusion strain gauge for preventing a cementing agent from overflowing without pressure.
Background
When the initial stress of a rock mass is measured by using a hole wall strain method, the strain before and after stress relief is usually measured by using a hollow inclusion strain gauge, so that the stress of the rock mass is calculated according to the strain. In the process of slowly pushing the strain gauge of the hollow bag body into the rock hole, the cementing agent poured into the hollow bag body has high mobility, so that the cementing agent easily flows out in advance under the condition that the front end has no pressure, the measurement result is inaccurate, and the measurement failure can be caused in serious cases.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides the hollow bag body strain gauge which has a simple structure and can improve the accuracy of a measurement result and prevent a cementing agent from overflowing without pressure.
In order to solve the technical problems, the invention adopts the following technical scheme: a hollow bag strain gauge for preventing a cementing agent from overflowing without pressure comprises a guide head, an installation column, a direction finder and a strain gauge, wherein a cylindrical hole with an open front end is formed in the installation column, the cylindrical hole is filled with the cementing agent, the rear end part of the guide head extends into the front end opening of the cylindrical hole, a sealing ring in sliding sealing fit with the inner wall of the cylindrical hole is arranged on the outer circle of the rear end of the guide head, a positioning structure is arranged between the outer circle of the rear end of the guide head and the installation column, a cementing agent extrusion channel with an open rear end is formed in the guide head, an elastic one-way valve is arranged in the cementing agent extrusion channel, and a cementing agent outflow hole communicated with the cementing agent extrusion channel is formed in the guide; the outer circumference of the mounting column is provided with a strain gauge and a positioning sleeve for fixing the strain gauge, the direction finder is coaxially mounted inside the rear side of the mounting column, and the rear end of the direction finder is connected with a cable which is connected with the strain gauge simultaneously.
The cementing agent extrusion channel is a blind hole coaxially formed in the guide head, a step groove is formed in the orifice of the blind hole of the guide head, the diameter of the step groove is larger than that of the blind hole, a spring is arranged in the step groove of the guide head, a limiting ring is fixedly arranged at the notch of the step groove on the rear end face of the guide head, a blocking piece is arranged on the inner side of the limiting ring, and the rear end of the spring is in top pressure fit with the limiting ring through the blocking piece.
The guide head is preceding cone section, well cylinder section and back cylinder section from preceding back in proper order, and preceding cone section is thick cone structure behind the preceding sharp, and the external diameter of well cylinder section equals the back end maximum diameter of preceding cone section, and well cylinder section external diameter is greater than back cylinder section external diameter, and the excircle of well cylinder section is equipped with preceding sealing washer.
And a rear sealing ring is arranged on the excircle of the rear part of the mounting column.
An annular groove is formed in the middle of the mounting column in the circumferential direction, a digital temperature sensor is arranged in the annular groove, and a cable is connected with the digital temperature sensor.
The positioning structure comprises two positioning pins, the front end part of the mounting column is provided with two jacks with central symmetry along the radial direction, the excircle central symmetry of the rear end of the guide head is provided with two positioning grooves, the two positioning grooves are respectively communicated with the two jacks in a one-to-one correspondence manner, and the positioning pins are correspondingly inserted into the jacks and the positioning grooves to temporarily connect the guide head and the mounting column into a whole.
The orientation device is connected with the mounting column through radially arranged pins.
By adopting the technical scheme, when the initial stress of the rock mass is measured by utilizing the hole wall strain method, the required rock hole is drilled and cleaned, the cementing agent is mixed in proportion, a proper amount of the cementing agent is poured into the cylindrical hole of the mounting column, then the rear end of the guide head is inserted into the front port of the cylindrical hole, the positioning groove corresponds to the insertion hole, and the positioning pin is inserted to enable the mounting column and the guide head to be connected into a whole. Then the front end of the installation rod is connected with the rear end of the installation column, the hollow bag body strain gauge is slowly fed into the rock hole, the baffle plate blocks the rear port of the cementing agent extrusion channel due to the elastic force of the spring in the process that the hollow bag body strain gauge moves in the hole, so as to prevent the cementing agent from overflowing, when the front end of the guide head reaches the bottom of the rock hole and contacts with the rock body, under the action of the external pressure of the forward propulsion of the installation rod, the positioning pin between the guide head and the installation column is subjected to the shearing force, the two positioning pins are cut off, the rear cylindrical section of the guide head extrudes the cementing agent in the cylindrical cavity, the pressure intensity of the cementing agent is rapidly increased, the pressure of the cementing agent on the baffle plate is larger than the elastic force of the spring, the baffle plate is separated from the limiting ring, the cementing agent breaks through the baffle plate and flows into the stepped groove, then enters the cementing agent extrusion channel, finally, and (3) completely extruding the cementing agent, solidifying the cementing agent between the rear cylindrical section and the hole wall of the rock hole by the strainmeter after the cementing agent is solidified, measuring the strain before and after the stress is relieved according to the strain gauge, and calculating the rock stress according to the strain.
The front sealing ring and the rear sealing ring play a role in limiting the forward or backward flow of the cementing agent, so that the cementing agent is solidified between the front sealing ring and the rear sealing ring and is solidified with the rock mass into a whole.
Digital temperature sensors are used to monitor temperature changes inside the rock bore.
The locating sleeve is made of epoxy resin, and the locating pin is made of aluminum wires and is easy to cut off.
In conclusion, the invention utilizes the spring one-way valve to provide certain elastic pressure for the cementing agent in the cylindrical cavity under the condition that the guide head is not pressurized, so that inaccurate measurement is prevented from being caused by overflow, the spring one-way valve is opened by utilizing the power of the transmission strain gauge after the cementing agent enters the bottom of the rock hole, and the cementing agent is ensured to be extruded out of the cylindrical cavity and solidified with the rock body into a whole after the strain gauge is transmitted in place, so that the problem that the cementing agent flows out in advance when the initial stress of the rock body is measured is solved, and the orderly measurement process and the accuracy of the measurement result are ensured.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is an enlarged view at a in fig. 1.
Detailed Description
As shown in fig. 1 and 2, the hollow bag strain gauge for preventing the pressureless outflow of the cementing agent comprises a guide head 1, an installation column 2, a direction finder 3 and a strain gauge 4, wherein the installation column 2 is internally provided with a cylindrical hole 5 with an open front end, the cylindrical hole 5 is filled with the cementing agent, the rear end part of the guide head 1 extends into the front end opening of the cylindrical hole 5, the excircle of the rear end of the guide head 1 is provided with a sealing ring 6 in sliding sealing fit with the inner wall of the cylindrical hole 5, a positioning structure is arranged between the excircle of the rear end of the guide head 1 and the installation column 2, the guide head 1 is internally provided with a cementing agent extrusion channel with an open rear end, the cementing agent extrusion channel is internally provided with an elastic one-way valve, and the guide head 1 is provided with a cementing agent outflow hole 7 communicated with the cementing agent extrusion channel; the outer circumference of the mounting column 2 is provided with a strain gauge 4 and a positioning sleeve 8 for fixing the strain gauge 4, the direction finder 3 is coaxially mounted inside the rear side of the mounting column 2, and the rear end of the direction finder 3 is connected with a cable 9 which is simultaneously connected with the strain gauge 4.
The cementing agent extrusion channel is a blind hole 10 coaxially arranged in the guide head 1, a step groove 11 is formed in the orifice of the blind hole 10 of the guide head 1, the diameter of the step groove 11 is larger than that of the blind hole 10, a spring 12 is arranged in the step groove 11 of the guide head 1, a limiting ring 13 is fixedly arranged on the rear end face of the guide head 1 at the notch of the step groove 11, a baffle piece 14 is arranged on the inner side of the limiting ring 13, and the rear end of the spring 12 is in top pressing fit with the limiting ring 13 through the baffle piece 14.
The guide head 1 is a front cone section, a middle cylinder section and a rear cylinder section from front to back in sequence, the front cone section is a cone structure with a front tip and a rear tip, the outer diameter of the middle cylinder section is equal to the maximum diameter of the rear end of the front cone section, the outer diameter of the middle cylinder section is larger than that of the rear cylinder section, and a front sealing ring 15 is arranged on the outer circle of the middle cylinder section.
The excircle of the rear part of the mounting column 2 is provided with a rear sealing ring 16.
An annular groove 17 is formed in the middle of the mounting column 2 along the circumferential direction, a digital temperature sensor 18 is arranged in the annular groove 17, and the cable 9 is connected with the digital temperature sensor 18.
The positioning structure comprises two positioning pins 19, the front end part of the mounting column 2 is radially provided with two jacks with central symmetry, the excircle central symmetry of the rear end of the guide head 1 is provided with two positioning grooves, the two positioning grooves are respectively communicated with the two jacks in a one-to-one correspondence manner, and the positioning pins 19 are correspondingly inserted in the jacks and the positioning grooves to temporarily connect the guide head 1 and the mounting column 2 into a whole.
The orientation device 3 is connected to the mounting post 2 by means of radially arranged pins 20.
When the initial stress of a rock body is measured by using a hole wall strain method, required rock holes are drilled and cleaned, then a cementing agent is mixed in proportion, a proper amount of the cementing agent is poured into the cylindrical hole 5 of the mounting column 2, then the rear end of the guide head 1 is inserted into the front end port of the cylindrical hole 5, the positioning groove corresponds to the insertion hole, and the positioning pin 19 is inserted to enable the mounting column 2 and the guide head 1 to be connected into a whole. Then the front end of the installation rod is connected with the rear end of the installation column 2, the hollow bag body strain gauge is slowly sent into the rock hole, in the process that the hollow bag body strain gauge moves in the hole, due to the elastic force of the spring 12, the blocking piece 14 blocks the rear port of the cementing agent extrusion channel, so that the outflow of the cementing agent is prevented, when the front end of the guide head 1 reaches the bottom of the rock hole and is contacted with a rock body, under the action of the external pressure of the forward pushing of the installation rod, the positioning pin 19 between the guide head 1 and the installation column 2 is subjected to shearing force, the two positioning pins 19 are cut off, the rear cylindrical section of the guide head 1 extrudes the cementing agent in the cylindrical cavity, the pressure of the cementing agent is rapidly increased, the pressure of the cementing agent on the blocking piece 14 is larger than the elastic force of the spring 12, the blocking piece 14 is separated from the limiting ring 13, the cementing agent breaks through the blocking piece 14 and flows into, and after the rear end of the guide head 1 is contacted with the bottom of the cylindrical cavity, the cementing agent is completely extruded out, the cementing agent is arranged between the rear cylindrical section and the hole wall of the rock hole, the strain gauge is solidified with an external rock body after the cementing agent is solidified, finally, the strain before and after the stress is relieved can be measured according to the strain gauge 4, and the rock body stress is calculated according to the strain.
The front sealing ring 15 and the rear sealing ring 16 play a role in limiting the forward or backward flowing of the cementing agent, so that the cementing agent is solidified between the front sealing ring 15 and the rear sealing ring 16 and is solidified with the rock mass into a whole.
The digital temperature sensor 18 is used to monitor temperature changes inside the rock bore.
The positioning sleeve 8 is made of epoxy resin, and the positioning pin 19 is made of aluminum wires and is easy to cut.
The present embodiment is not intended to limit the shape, material, structure, etc. of the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (7)
1. The utility model provides a prevent that binder is non-pressure excessive hollow inclusion strainometer which characterized in that: the guide head comprises a guide head, an installation column, a direction finder and a strain gauge, wherein a cylindrical hole with an open front end is formed in the installation column, cementing agent is filled in the cylindrical hole, the rear end part of the guide head extends into the front end port of the cylindrical hole, a sealing ring in sliding sealing fit with the inner wall of the cylindrical hole is arranged on the outer circle of the rear end of the guide head, a positioning structure is arranged between the outer circle of the rear end of the guide head and the installation column, a cementing agent extrusion channel with an open rear end is formed in the guide head, an elastic one-way valve is arranged in the cementing agent extrusion channel, and a cementing agent outflow hole communicated with the cementing agent extrusion channel is formed in the; the outer circumference of the mounting column is provided with a strain gauge and a positioning sleeve for fixing the strain gauge, the direction finder is coaxially mounted inside the rear side of the mounting column, and the rear end of the direction finder is connected with a cable which is connected with the strain gauge simultaneously.
2. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: the cementing agent extrusion channel is a blind hole coaxially formed in the guide head, a step groove is formed in the orifice of the blind hole of the guide head, the diameter of the step groove is larger than that of the blind hole, a spring is arranged in the step groove of the guide head, a limiting ring is fixedly arranged at the notch of the step groove on the rear end face of the guide head, a blocking piece is arranged on the inner side of the limiting ring, and the rear end of the spring is in top pressure fit with the limiting ring through the blocking piece.
3. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: the guide head is preceding cone section, well cylinder section and back cylinder section from preceding back in proper order, and preceding cone section is thick cone structure behind the preceding sharp, and the external diameter of well cylinder section equals the back end maximum diameter of preceding cone section, and well cylinder section external diameter is greater than back cylinder section external diameter, and the excircle of well cylinder section is equipped with preceding sealing washer.
4. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: and a rear sealing ring is arranged on the excircle of the rear part of the mounting column.
5. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: an annular groove is formed in the middle of the mounting column in the circumferential direction, a digital temperature sensor is arranged in the annular groove, and a cable is connected with the digital temperature sensor.
6. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: the positioning structure comprises two positioning pins, the front end part of the mounting column is provided with two jacks with central symmetry along the radial direction, the excircle central symmetry of the rear end of the guide head is provided with two positioning grooves, the two positioning grooves are respectively communicated with the two jacks in a one-to-one correspondence manner, and the positioning pins are correspondingly inserted into the jacks and the positioning grooves to temporarily connect the guide head and the mounting column into a whole.
7. The strain gauge for a hollow inclusion capable of preventing pressureless outflow of cementing agent according to claim 1, is characterized in that: the orientation device is connected with the mounting column through radially arranged pins.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110119310.5A CN112729632A (en) | 2021-01-28 | 2021-01-28 | Hollow bag strain gauge for preventing cementing agent from overflowing without pressure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110119310.5A CN112729632A (en) | 2021-01-28 | 2021-01-28 | Hollow bag strain gauge for preventing cementing agent from overflowing without pressure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112729632A true CN112729632A (en) | 2021-04-30 |
Family
ID=75594482
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110119310.5A Pending CN112729632A (en) | 2021-01-28 | 2021-01-28 | Hollow bag strain gauge for preventing cementing agent from overflowing without pressure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112729632A (en) |
-
2021
- 2021-01-28 CN CN202110119310.5A patent/CN112729632A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110849524A (en) | Fixing device and mounting method for soil pressure box of shield tunnel | |
| CN112461189B (en) | Ground stress measuring strain gauge | |
| CN112729632A (en) | Hollow bag strain gauge for preventing cementing agent from overflowing without pressure | |
| CN214121462U (en) | Hollow bag strain gauge for preventing cementing agent from overflowing without pressure | |
| CN210833966U (en) | Shield tunnel soil pressure cell fixing device | |
| CN205538058U (en) | Novel ground stress test device | |
| CN113820059B (en) | Positioning device for hollow inclusion for ground stress measurement and use method | |
| CN202706972U (en) | Hydraulic returnable fishing spear | |
| CN205969857U (en) | Sheath extrusion tooling of production GYXTW optical cable | |
| CN110789055B (en) | Forming structure of blind hole nut on side of moving die | |
| CN115575025B (en) | Main control pretightning force anchor rod, cable pressure sensor | |
| CN206154670U (en) | Ring type injection molding machine clamp force sensor for tester | |
| CN211849372U (en) | Novel static sounding probe | |
| CN214944190U (en) | Anti-return-spitting measurable pressure water distributor | |
| CN113445995A (en) | Temperature testing device used in cooperation with temporary plugging agent | |
| CN210464689U (en) | Temperature measurement structure, bearing temperature measuring device and stranding machine | |
| CN112983520A (en) | Multistage pressure type stock that lets suitable for soft rock large deformation tunnel is strutted | |
| CN102313501A (en) | Tooling for detecting perpendicularity between penetration hole and groove surface of reduction gearbox output shaft | |
| CN109341922B (en) | Hollow inclusion small hole installation centering adjustment device for ground stress test and use method | |
| CN203344222U (en) | Mold for product of cylinder with deep cavity and groove in wall | |
| CN114088262B (en) | Hollow inclusion stress meter with visual guiding and positioning functions and use method thereof | |
| CN111535801A (en) | Sleeve pipe pressure measuring device | |
| CN115420251B (en) | Twelve-component small-aperture hole bottom strain gauge | |
| CN117782382A (en) | Hollow inclusion stress meter capable of accurately sensing whole installation process and use method | |
| CN110306932A (en) | The local compacted booster compression mechanism of landwaste |
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 |