Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
  • G01V9/00—Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
• • 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
  • E21B49/001—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 specially adapted for underwater installations
• • 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 relates to a method for establishing the physical profile of soil layers, and in particular the property of soils designated by
• the present invention achieves this result in conditions of speed and precision that no other technique can fulfill. lu
• the method according to the invention for establishing the cohesion curve of an underwater soil in particular but not exclusively at great depth, consists in dropping from the surface a machine whose shape is optimized so as to reach by reaching basically
• T5 a sufficiently high descent speed to then penetrate into a significant thickness of the ground, and to provide this machine with sensors transforming the various resistances encountered by the machine by crossing the ground into electrical signals which are 0 processed as and when required by electronic means and IT contained in the machine itself, so as to transmit directly to the surface the information sought on the nature of the soil layers crossed.
• the method according to the invention consists in capturing with the same machine on the one hand the forces resulting from the resistance encountered by the latter when penetrating into the ground and on the other hand the lateral forces resulting from friction between the machine and the ground.
• the invention also relates to a machine adapted to the implementation of this method, this machine being characterized, first of all, in that it has an optimized shape to take, during its descent from the surface to the bottom , the maximum acceleration, and meet the bottom with the maximum speed, so as to penetrate the ground to the maximum depth, secondly in that it is equipped with stress sensors continuously measuring the bonding forces between the body of the machine and its tip and its rear and the lateral stresses resulting from the friction of the machine on the successive layers of the ground, and thirdly in that it constitutes at the same time a hyperbar container in which are housed a conditioner of the signals delivered by the sensors, an amplifier of these signals and a system for storing these signals, itself consisting of a microcomputer and a converter performing the sampling of these signals according to their frequencies uences.
• Such a device is connected to the surface by any means allowing the permanent transmission of the signals thus processed, so that the soil cohesion curve can be established instantly with each release. of the craft.
• An electrical conductor is obviously suitable for this purpose, but it is also possible to use other means such as optical fibers.
• each of said sensors comprises means for guiding by elastic blades, which do not introduce any stiffness and which, moreover, are perforated, which allows the passage of water, so that in principle, the hydrostatic pressure being exerted on the two sides of these blades, it is not likely to distort the measurement.
• each sensor is completely autonomous and independent at the mechanical level, which makes it easy to exchange and individually calibrate them in the laboratory.
• the machine also comprises a control rod, mounted in said machine at a point where the temperature and the pressure are the same as those which are transmitted to the bars supporting the strain gauges, so to compensate for the hydrostatic component and the thermal drift which would risk distorting the measurements of said gauges if they were not constantly taken into account.
• the machine comprises a three-dimensional accelerometer, providing information on the inertia effects and therefore also ensuring the consistency of the measurement results with respect to these inertia effects.
• the invention relates to a particular and original embodiment of the parietal sensor intended for measuring the lateral forces undergone by the machine and resulting from friction between said machine and the ground.
• a parietal sensor is characterized in that it comprises an element sensitive to external lateral friction, connected to a base secured to the machine by elastic blades, and whose displacements relative to said base are transmitted to a measurement gauge through the deformations of a measurement element such as a rod embedded in the fixed base at one of its two ends, and positioning the movable sensitive element longitudinally relative to this fixed base.
• a measurement element such as a rod embedded in the fixed base at one of its two ends
• the operation is very rapid, asking for a few minutes.
• a device according to the invention takes two minutes to reach a bottom of 6000 meters, then 1 second to sink 40 meters.
• the results are instantaneous and do not require an analysis as is the case for carrots.
• FIG. 1 is a very schematic view in axial section of the machine
• FIG. 2 is an axial section of the front of the machine
• FIG. 3 is an axial section of the device mounted at the rear of the machine
• FIG. 4 is a very schematic axial section of a wall sensor according to the invention, illustrating the principle of its operation
• FIG. 5 is a view similar to FIG. 4, illustrating in more detail the practical embodiment of a wall sensor
• FIG. 6 is a top view of the sensor of FIG. 5, and
• Figure 7 is a section along VII-VII of Figure 6.
• REPLACEMENT SHEET the machine consists of an envelope or body 1 whose overall profile is optimized as described in French patent No. 85.09355 of the applicant. It is thanks to this optimized profile that the machine, dropped vertically from a surface structure, very quickly takes a very high speed, ensuring its maximum penetration into the ground when it reaches the bottom.
• FIG. 2 Behind the head or cone of penetration 2, 0 is mounted in the machine an apparatus or module 3 for measuring the forces resulting from the resistance encountered by the machine during its penetration into the ground. This module 3 is described in more detail below with reference to FIG. 2. 5 Towards the rear of the machine is similarly mounted an apparatus or module 4 for measuring the connection forces between the rear of the 'machine and body 1. This module 4 is described in more detail below with reference to Figure 3.' - ) Finally on the side of the machine is mounted an apparatus or module 5 for measuring the lateral forces resulting friction between the machine and the ground. This module 5 is described in more detail below with reference to FIGS. 4 to 7.
• modules 3,4 and 5 are connected by connections 6, 7 and 8 to a processing unit 9, housed in the heart of the craft, and which is itself connected by a suitable connection 10 to the surface structure.
• the module 3 consists of an outer cage 11 in which are mounted two elastic diaphragms 12 and 13, for the lateral guidance of a bar 14, arranged in the axis of the machine by resting on the bottom of the cage and carrying gauges 14 '.
• the penetration cone 2 transmits the forces encountered by the machine to these gauges by means of a threaded mounting sleeve 15 which leaves a clearance 16, allowing the passage of water inside the cage 11
• the rear module 4 also consists of a cage 17 in which are mounted two elastic blades 18 and 19 serving for the lateral guidance of a bar 20, arranged in the axis of the machine carrying gauges 20 '.
• a plate 21 is used for fixing the module 4 to the body 1, so that the gauges 20 ′ allow the connection forces between this body 1 and a rear plate 22 fixed to the bar 20 to be measured.
• Knowledge of the measurements of gauge 30 therefore provides the means of compensating for the hydrostatic component and the thermal drift which would risk distorting the measurements if they were not taken into account.
• the gauge 30 is sufficient for the calculation of the measurements carried out by all. the sensors of the machine.
• a base 42 on which is adapted an outer plate 43..through two elastic blades 44 and 45, and which is kept at constant distance from the base 42 by a bar 48 working in bending.
• the internal end 48 ′ of the bar 48 is embedded in the base 42, while its external head 48 ′′ has the shape of a ball joint housed in a recess 60 in the plate 43, so as to freely follow the movements of this plate 43 parallel to the direction XX ′.
• This bar 48 carries strain gauges 46 and 47, arranged on either side.
• the external wall 43 can thus move parallel to the axis of the machine, by relative to the body 41 of the machine, the operation of the device is the following: the machine 41 moving in the direction X'X, within an environment such as loose ground, the friction which it undergoes on the part of this ground determine braking, and consequently a displacement of the plate 43, in the direction XX 'relative to the machine 41.
• This displacement results in a deformation of the element 48, which is measured by. the gauges 46-47 and this measurement is taken as an element of appreciation of said friction, and integrated with the other measurements transmitted by the head and tail sensors of the machine in the study of said earth -
• FIGS. 5-6-7 The practical implementation of such a sensor is illustrated in the detailed views in FIGS. 5-6-7, where the corresponding elements have been designated by the same reference numerals, assigned with a "" sign.
• the measuring element 48 ' has the form of a plate 50 fixed on the base of four screws 52, and extending towards the plate 43' by a rod 53 on the end part of which act the screws 54-55.
• the gauges 49 ' are placed on this rod. Any movement of the sensitive plate 43 'within the limits of the travel e.' induced by the longitudinal friction of the machine on the medium traversed results in a deformation of the rod 48 ', measured by the gauges 49', the signals of which are transmitted, like those of the head and tail gauges, to the system 9 amplification and storage of these signals, then their sampling, and their retransmission by any means appropriate to the surface structure.
• parietal sensor which has just been described operates regardless of the medium in which the machine 41 (or 41 ′) moves, so that the application of the invention is not limited to the penetrants intended to the study of marine soils, but can extend to the study of all other environments, loose or fluid.
• a three-dimensional accelerometer 61 is also housed in the sealed enclosure of the machine, in order to allow corrections to be made to the measurements required by the existence of the inertia effects.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Geochemistry & Mineralogy (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Structural Engineering (AREA)
• Paleontology (AREA)
• Soil Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Civil Engineering (AREA)
• Analytical Chemistry (AREA)
• Chemical & Material Sciences (AREA)
• General Physics & Mathematics (AREA)
• Geophysics (AREA)
• Testing Or Calibration Of Command Recording Devices (AREA)
• Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=9348723

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• 1987
  • 1987-03-04 FR FR8703136A patent/FR2611922B1/fr not_active Expired
  • 1987-07-29 EP EP19870904896 patent/EP0304434A1/de not_active Withdrawn
  • 1987-07-29 WO PCT/FR1987/000300 patent/WO1988006739A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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