Soil stabilization process and associated system.

Abstract

Building stabilization process (BAT1) comprising the following steps: Preparatory steps including: Steps for assembling a measuring device comprising a second tube (200) and a support (sup1), inside the second tube (200), carrying a first thermal probe; Then, steps for delivering a composition including a step during which the composition (COM1), thus injected, exits a first tube (100, 100'), through a first outlet (S1, S1') of the first tube (100, 100'), and spreads into the ground (SOL1); Then, measurement steps including: A temperature measurement by the first thermal probe. Figure for the abbreviation: Figure 1

Description

Title of the invention: Method for stabilizing soil and associated system. Technical field and prior art

[0001] The present invention relates to the stabilization of soils, and possibly as a consequence, of constructions such as buildings possibly erected on them, in particular when the soils have proven to be unstable or subject for example to the phenomenon of shrinkage-swelling (in the case of a clay soil, for example).

[0002] A process is known for stabilizing soil, consisting of injecting into the soil, through a first tube, a composition which diffuses and takes hold in voids or crevices in the soil, thus stabilizing the soil and a construction by action on the soil on which it is located.

[0003] This method may include monitoring a building elevation level and / or a ground surface using a laser level or other measuring system.

[0004] Detection of an increase in the elevation level of the construction and / or of a ground surface may indicate that the ground and consequently the construction possibly erected on the ground are stabilized, and that the injection should be stopped.

[0005] However, this monitoring does not allow us to ensure sufficient distribution of the composition in the soil. Description of the invention

[0006] The invention aims to remedy this drawback and relates to a method for stabilizing soil (and / or a structure, for example a building) comprising the following steps: - Preparatory steps including: • Steps for assembling a measuring device comprising a second tube with a wall, and a support carrying a first thermal probe and possibly a second thermal probe; the steps for assembling the measuring device comprising inserting the second tube into the ground (for example, vertically), the wall separating the inside of the tube from the ground, and then inserting the support into the second tube so as to position the first thermal probe inside the second tube, for example, at a first location, and possibly the second thermal probe, inside the second tube, for example at a second location, - Then, the steps for delivering the composition include: • An injection (under pressure or by gravity) of the composition into a first tube inserted into the ground, and • A first step during which the injected composition exits the first tube (in other words: the composition is allowed to exit the first tube), through a first outlet (in other words: a first opening) of the first tube, and spreads (in other words: diffuses) into the soil, and optionally • A second step during which the composition, thus injected, exits the first tube (in other words: the composition is allowed to exit the first tube), through a second outlet (in other words: a second opening) of the first tube, and spreads (in other words: diffuses) into the soil,

[0007] the composition, taking hold, particularly in voids (in other words: in crevices) of the soil, and heating up, and for example swelling (alternatively, the composition is not expansive), once spread into the soil, as a result of an exothermic chemical reaction, - Then, measurement steps including: • An initial temperature measurement, using the first thermal probe, for example at the first location, and optionally • A second measurement of a second temperature, using the second thermal probe, for example at the second location.

[0008] The invention makes it possible to ensure sufficient distribution of the composition in the soil in a particularly simple and economical way. In particular, the support, thanks to its insertion into the second tube, can be removed and / or reused after the measurement step for another site or for other measurements at other locations of the ongoing site.

[0009] For example, the first location is closer to the first output than to the second output, and the second location is closer to the second output than to the first output. However, preferably, the first and second locations have arbitrary positions relative to the first and second outputs.

[0010] The first tube comprising a first outlet and, possibly, a second outlet, the first tube is a perforated tube.

[0011] For example, the thermal probes (e.g., the first thermal probe and / or the second thermal probe) are or include thermocouples. Alternatively, the measuring medium consists of a coaxial cable.

[0012] Thus, the support and the first and / or second thermal probe may be combined (in the case of coaxial cable, for example). Alternatively, the support carries the first and / or second thermal probe (in the case of thermocouples, for example).

[0013] The measurement steps can be implemented, and / or repeated between 1 second and 4 hours, for example between thirty minutes and four hours or between thirty seconds and ten minutes, after the delivery steps.

[0014] The measurements can be initiated a few minutes before the injection (i.e., before delivery), for example, in cases where one or more reference temperature measurements are required,

[0015] The composition is, for example, a polymer resin and the chemical reaction is polymerization. The composition is, for example, a polyurethane resin. Alternatively, it could be an epoxy resin or a cementitious grout.

[0016] By “set”, we mean, for example, that the composition passes into a solid state (from a liquid state) once dispersed in the soil, as a result of the exothermic chemical reaction.

[0017] The (chemical) "setting" reaction of the composition is understood in a broad sense, as it can correspond to the setting reaction of a cementitious grout as well as a polymerization reaction of a polymer resin. After this setting reaction, the composition is in a rigid (hardened) solid state or in a deformable elastic solid state (such as a flexible gel, for example).

[0018] The composition may have an expansive character (in volume), a characteristic which may prove advantageous for certain soil stabilization techniques.

[0019] Polyurethane resin is for example a one-component resin or a two-component resin.

[0020] A single-component polyurethane resin is water-reactive: it is the presence of water in the soil that causes the chemical reaction which is a polymerization reaction, a reaction which generally has an exothermic character.

[0021] In the case of a two-component resin, the preparation steps may include a mixing step, for example of a polymer with a catalyst.

[0022] The step of injecting such a composition is well known to those skilled in the art and does not need to be detailed here. It can be carried out using a pump.

[0023] According to one embodiment, similarly, the first tube comprises an additional outlet (in addition to the first and second outlets) through which the composition exits during the injection step, and / or the support comprises a probe additional thermal probe (in addition to the first thermal probe and the second thermal probe) positioned, during the assembly steps, for example at a third location, possibly closer to the third output than to the first and second outputs, the measurement steps including an additional measurement of an additional temperature by the additional thermal probe, for example at the third location.

[0024] Alternatively, there is no additional output and / or no additional measurement.

[0025] The first tube is for example metallic and / or is driven vertically into the ground.

[0026] The insertion stage is of course within the capabilities of a person skilled in the art. It may include dynamic driving (electric hammer driving), other insertion techniques (for example including drilling) remaining possible.

[0027] The first outlet and / or the second outlet and / or the additional outlet is, for example, located in an area of ​​the ground under a building or near it area.

[0028] For example, the first output (and / or the third output) is vertical to the second output (and / or the third output), but an offset is of course possible.

[0029] For example, the first output and the second output (and possibly the third output) are two different outputs of the first tube.

[0030] Alternatively, the first outlet, the second outlet, and possibly the additional outlet are the same outlet of the first tube. In this case, the composition may exit from this same outlet, then the tube is partially withdrawn from the ground, then the composition may exit from this same outlet, then possibly the tube is partially withdrawn from the ground, then the composition may exit from this same outlet.

[0031] Following the injection steps and the setting reaction (and / or, for example, the hardening) of the composition, the first and / or second tube may become embedded in the composition and thus sealed in the ground. Thanks to the invention, following the measurement steps, the support can be completely removed from the ground (and then reused), despite the second tube becoming embedded in the composition and potentially sealed in the ground.

[0032] According to one embodiment, the preparatory steps include, after the assembly step (and before the delivery steps), a fourth measurement of a fourth temperature at the second location by the second probe, the measurement steps including a comparison between a threshold (in other words: a second threshold) and a second (differential) value equal to the second temperature minus the fourth temperature.

[0033] The fourth temperature is thus a reference temperature of the soil measured before a temperature rise resulting from the chemical polymerization reaction which has an exothermic character.

[0034] If the second value is greater than this threshold, then we can consider that the composition is present near the second location, or that the composition has been injected in sufficient quantity near the second location.

[0035] This threshold can be, for example, between one tenth of a degree Celsius and fifty degrees Celsius.

[0036] According to one embodiment, this threshold is, for example, between half a degree Celsius and two degrees Celsius. In this case, the measurement steps can be implemented, for example, and / or repeated between thirty minutes and four hours after the delivery steps. It is thus possible to detect a slow diffusion of the heat produced by the chemical reaction when, for example, the second location is far from the second outlet and / or due to the nature of the soil.

[0037] Alternatively, this threshold is, for example, between two degrees Celsius and fifty degrees Celsius. In this case, the measurement steps can be implemented, for example, and / or repeated between thirty seconds and ten minutes after the delivery steps. It is thus possible to detect a rapid diffusion of the heat produced by the chemical reaction when, for example, the second location is close to the second outlet and / or due to the nature of the soil.

[0038] Alternatively, it can be considered that the composition is present in the vicinity of the second location and / or that the composition has been injected in sufficient quantity in the vicinity of the first location as soon as the second temperature is above a threshold, for example between thirty degrees Celsius and fifty degrees Celsius.

[0039] According to one embodiment, the second location is at the same depth in the ground as the second exit.

[0040] Alternatively, the second location and the second exit can also be at different depths in the ground.

[0041] According to one embodiment, the second location is at a (horizontal) distance from the second exit of between 5 centimeters and 99 centimeters. Of course, other distances are possible.

[0042] According to one embodiment, the preparatory steps include, after the assembly step (and before the delivery steps), a third measurement of a third temperature at the first location by the first probe, the measurement steps comprising a comparison between a threshold (in other words: a first threshold) and a first (differential) value equal to the first temperature minus the third temperature.

[0043] If the first value is greater than this threshold, then we can consider that the composition is present in the vicinity of the first location.

[0044] This threshold can be, for example, between one tenth of a degree Celsius and fifty degrees Celsius.

[0045] According to one embodiment, this threshold is, for example, between half a degree Celsius and 2 degrees Celsius. In this case, the measurement steps can be implemented, for example, and / or repeated between thirty minutes and four hours after the delivery steps. It is thus possible to detect a slow diffusion of the heat produced by the chemical reaction when, for example, the first location is far from the first outlet and / or due to the nature of the soil.

[0046] Alternatively, this threshold is, for example, between two degrees Celsius and fifty degrees Celsius. In this case, the measurement steps can be implemented, for example, and / or repeated between thirty seconds and ten minutes after the delivery steps. It is thus possible to detect a rapid diffusion of the heat produced by the chemical reaction when, for example, the first location is close to the first outlet and / or due to the nature of the soil.

[0047] Alternatively, the composition can be considered to be present in the vicinity of the first location when the first temperature is above a threshold, for example between thirty degrees Celsius and fifty degrees Celsius.

[0048] According to one embodiment, the first location is at the same depth in the ground as the first exit.

[0049] Alternatively, the first location and the first exit can also be at different depths in the ground.

[0050] According to one embodiment, the first location is at a distance from the first exit of between 5 centimeters and 99 centimeters.

[0051] Of course other distances are possible.

[0052] For example, the delivery steps can be implemented, in addition, with another tube in the same way as with the first tube, and the first location and the second location are situated between the first tube and the other tube.

[0053] It can also be foreseen, in a similar manner, that the support has more than 3 thermal probes (in other words: and / or more than 3 locations) and / or that the first tube has more than 3 outlets. For example, the number of thermal probes may exceed the number of outlets or vice versa.

[0054] The thermal probes (in other words: and / or more locations) can be located at depths spaced (for example, vertically) apart from each other, for example, from 20 centimeters to 99 centimeters.

[0055] The first tube may have outlets at depths spaced (for example, vertically) apart from each other, for example, from 20 centimeters to 99 centimeters.

[0056] For example, the first outlet, and / or possibly the second outlet, and / or possibly the additional outlet, and / or the first location, the second location, and / or possibly the third location are located at depths in the ground of less than ten meters.

[0057] According to one embodiment, the support includes a rod carrying the first thermal probe and / or the second probe (and / or the additional probe).

[0058] Alternatively, for example, the support includes a cable (or wire) inserted into the tube carrying the first thermal probe and / or the second probe (and / or the additional probe), during the measurement steps.

[0059] The stem is, for example, made of plastic. Alternatively, the stem is made of metal.

[0060] According to one embodiment, electrical wires connected to the first probe (and / or to the second probe and / or to the additional probe) pass through the rod to transmit information representative of the first temperature (and / or the second temperature and / or the additional temperature) from the first probe (and / or the second probe and / or the additional probe) (to a reading interface or a computer which will process this information, for example which will display this information and / or the first value and / or the second value, after possibly calculating the first value and / or the second value).

[0061] Alternatively, the electrical wires may be outside the rod, or the first probe (and / or the second probe and / or the additional probe) may transmit (to the computer) the information representing the first temperature and / or the second temperature (and / or the additional temperature) by radio frequency communication.

[0062] According to one embodiment, the second tube is made of a material with a thermal conductivity greater than 1 watt per meter-kelvin, for example, greater than 10 watts per meter-kelvin or, for example, greater than 100 watts per meter-kelvin (and, for example, up to 5000 watts per meter-kelvin). The second tube is, for example, made of metal, such as steel or aluminum. Alternatively, for example, it is a mineral material such as graphite, or alternatively, graphene. It can also, of course, be a composite material.

[0063] Alternatively, the second tube can be made of polymer material.

[0064] According to one embodiment, the first thermal probe and / or between the second thermal probe (and / or the additional thermal probe) is in direct contact with the wall or indirectly with the wall via a thermal bridge (preferably in a solid material), during the measurement steps.

[0065] Alternatively, the first thermal probe and / or the second thermal probe (and / or the additional probe) are / are separated from the wall by a closed air ring (in other words: the first thermal probe and / or the second thermal probe is not in contact, direct or indirect, with the wall), during the measurement steps.

[0066] For example, the thermal bridge has a thermal conductivity greater than 1 Watt per meter-kelvin, for example greater than 10 Watt per meter-kelvin or for example greater than 100 Watt per meter-kelvin (and for example, up to 5000 Watt per meter-kelvin).

[0067] For example, the thermal bridge is made of metal, for example steel or aluminum. Alternatively, for example, it is a mineral material such as graphite, or alternatively graphene. It can also, of course, be a composite material.

[0068] For example, the first thermal probe and / or the second thermal probe (and / or the additional probe) and / or the thermal bridge is fixed relative to the rod, during the assembly steps.

[0069] Alternatively, for example, the first thermal probe and / or the second thermal probe (and / or the additional probe) and / or the thermal bridge are / are movable transversely with respect to the longitudinal axis of the rod during the assembly steps. For example, the first thermal probe and / or the second probe and / or the thermal bridge are / are, during or before the measurement steps (or during the assembly steps), pushed against the wall by an elastic element, for example a spring, attached to the rod.

[0070] According to one embodiment, during the assembly steps, there is a gap, for example of at least 1 millimeter (for example up to 10 millimeters), between the wall and an outer surface of the rod, over at least 80% (or at least 90%) of a length of the rod (for example, the length is vertical during the assembly steps), which facilitates the assembly step.

[0071] Alternatively, for example, but not limited to, the wall and / or outer surface of the rod may comprise a low coefficient of friction coating such as polytetrafluoroethylene (PTFE).

[0072] According to one embodiment, the first probe protrudes from the outer surface of the rod, at least during the measurement steps.

[0073] According to one variant, the rod has inflatable segments, each of these segments being able to be inflated (for example with air), after the insertion step, so as to bring the first thermal probe and / or the second probe (and / or the additional probe) and / or the thermal bridge into contact with the wall during the measurement steps.

[0074] The invention also relates to a soil (and / or structure, for example building) stabilization system comprising: - A delivery device capable of implementing the delivery steps of the stabilization process, including the first tube, - A measuring device capable of implementing the measurement steps of the stabilization process, including the second tube and the support.

[0075] Such a delivery device is well known to those skilled in the art and does not need to be described in detail here. It may include a pump for injecting the composition.

[0076] The measuring device may include the support, and the second tube.

[0077] Although they are not repeated here, the advantages and characteristics of the system are identical (mutatis mutandis) to those of the above process. Brief description of the drawings

[0078] The invention will be better understood upon reading the detailed description that follows, the non-limiting examples of its implementation, and upon examination of the accompanying drawings, in which:

[0079] [Fig-1] represents a soil stabilization system,

[0080] [Fig.2] represents a support in the stabilization system,

[0081] [Fig.3] represents a method, according to an embodiment of the invention, put into work by the system of [Fig.1]. Detailed description

[0082] Fig. 1 represents a soil stabilization system.

[0083] The stabilization system includes a delivery device well known to those skilled in the art.

[0084] [Fig.1], the only elements represented of the delivery device are tube 100 and tube 100'.

[0085] The delivery device also includes an injection device such as a pump not shown.

[0086] The stabilization system also includes a measuring device comprising a support supl, and a tube 200.

[0087] With reference to [Fig.3], at step S00, the tube 200 is inserted into the ground SOL1 (for example, the tube 200 is driven in by hammering or inserted into a suitable borehole previously made).

[0088] At step S10, the support supl is inserted into the tube 200 (for example manually).

[0089] The support supl is shown alone [Fig.2]. The support supl includes a rod T200 to which is attached a thermal probe S210 then at location LOC1 (after step S10), a thermal probe S220 then at a location LOC2 (after step S10), and a thermal probe S230 then at a location LOC3 (after step S10).

[0090] For example, the tube 200 is made of steel and the rod T200 is tubular in shape and made of plastic material.

[0091] [Fig.1], the thermal probe S210, the thermal probe S220 and the thermal probe 230 are in direct contact with the wall of the tube 200.

[0092] For example, the thermal probe S210, the thermal probe S220 and the thermal probe S230 are in contact with the wall of the tube 200, via an aluminum thermal bridge (not shown).

[0093] For example, there is a J200 clearance between the wall of the tube 200 and an outer surface of the rod T200.

[0094] At step S20, the thermal probe S210, the thermal probe S220 and the thermal probe S230 measure the temperature respectively at location LOC1, at location LOC2, and at location LOC3, and transmit these first temperatures to the computer 0200 via wires (not shown) passing inside the rod T200.

[0095] At step S30, the composition C0M1 is injected into tube 100 and tube 100' by the delivery device, in particular using a pump, in a manner known to those skilled in the art.

[0096] At step S40, the composition C0M1, thus injected at step S30, exits via: - One output S1, one output S2, and one output S3 of tube 100, located 90 cm apart, - An output SI', an output S2', and an output S3' of tube 100', located 90 cm apart.

[0097] The SI outlet, the S2 outlet, and the S3 outlet, the SI' outlet, the S2' outlet, and the S3' outlet are located in an area of ​​the ground under the BATI construction or near this area.

[0098] At step S50, the composition C0M1 spreads (diffused) into the PR1 zone, the PR2 zone, the PR3 zone, the PRT zone, the PR2' zone, the PR3' zone, heated and set (and for example, swelled and hardened) by polymerization of the composition C0M1.

[0099] At step S60, the thermal probe S210, the thermal probe S220 and the thermal probe S230 measure the temperature again respectively at location LOC1, at location LOC2, and at location LOC3, and transmit these second temperatures to the computer 0200 via the wires mentioned in step S20.

[0100] Location LOC1, location LOC2, and location LOC3 are at a distance dhl from output SI, output S2, output S3, output SI', output S2', and output S3'. This distance dhl is, for example, equal to 60 centimeters.

[0101] At step S70, the computer 0200 calculates the difference between the temperature measurement at step S20 and the temperature measurement at step S60 for each location among location LOC1, location LOC2 and location LOC3.

[0102] Steps S60 and S70 are then repeated for 30 minutes (without injection of additional composition), every minute.

[0103] If, for a location among location LOC1, location LOC2, and location LOC3, the maximum of the differences calculated in steps S70 is less than a threshold whose value is fixed at 5 degrees Celsius, for example, then the computer 0200 displays an alert message indicating a potential deficit of spilled resin at that location. For example, in [Fig. 1], such a deficit would be detected for location LOC1.

[0104] Conversely, if for a given location the maximum difference calculated in steps S70 is strictly greater than 5 degrees Celsius, it can be considered that sufficient resin has been dispensed, i.e., a significant quantity capable of meeting the need at that location. For example, in [Fig. 1], resin injection would be detected for locations LOC2 and LOC3.

[0105] According to one embodiment, the positions of the locations LOI, LO2 and LOC3 can be uncorrelated with the positions of the outlets PR1, PR2, PR3, PR1', PR2', PR3'. The number of locations (in other words, temperature measurement points) can also be uncorrelated with the number of outlets of tube 100 on the one hand, and with the number of outlets of tube 100' on the other.

[0106] According to one variant, the measured temperatures can be displayed directly by the computer 0200 in real time (by a digital display or graphs), allowing direct exploitation by the operator who calculates the differences and compares them to the characteristic threshold of 5 degrees Celsius.

[0107] At step S80, the support supl can be removed from the floor SOL1 and from the tube 200.

[0108] Following the setting reaction of composition C0M1, tube 100, tube 100' and / or tube 200 may remain trapped in composition C0M1 and are thus sealed in soil SOL1.

Claims

Demands

1. A method for stabilizing a soil (SOL1) comprising the following steps: - Preparatory steps comprising: • Steps for assembling a measuring device comprising a second tube (200) having a wall, and a support (supl) comprising a first thermal probe (S210), the steps for assembling the measuring device comprising inserting the second tube (200) into the soil (SOL1), the wall then separating the inside of the tube from the soil (SOL1), then, inserting the support (supl) into the second tube (200), so as to position the first thermal probe (S210) at a first location (LOC1), inside the second tube (200), - Then, steps for delivering a composition comprising: • Injecting the composition (C0M1) into a first tube (100, 100') inserted into the soil (SOL1), and • A first step during which the composition (C0M1), thus injected, exits the first tube (100, 100'),through a first outlet (SI, SU) of the first tube (100, 100'), and spreads into the soil (SOL1), the composition (C0M1) setting and heating up, once spread into the soil (SOL1), as a result of an exothermic chemical reaction, - Then, measurement steps including: • A first measurement of a first temperature, at the first location (LOC1), by the first thermal probe (S210).

2. A stabilization method according to the preceding claim, wherein the preparatory steps include, after the assembly step, a third measurement of a third temperature at the first location (LOC1) by the first probe (S210), the measurement steps including a comparison between a threshold and a first value equal to the first temperature minus the third temperature.

3. Stabilization method according to any one of the preceding claims wherein the first location (LOC1) is at the same depth in the ground as the first exit (SI, SI').

4. Stabilization method according to any one of the preceding claims wherein the first location (LOC1) is at a distance (dhl) from the first exit (SI, SI') of between 5 centimeters and 99 centimeters.

5. Stabilization method according to any one of the preceding claims wherein the support (supl) comprises a rod (T200) carrying the first thermal probe.

6. Stabilization method according to the preceding claim in which electrical wires connected to the first probe pass through the rod (T200) to transmit information representative of the first temperature from the first probe (S210).

7. Stabilization method according to any one of the preceding claims wherein the second tube (200) is made of a material with a thermal conductivity greater than 10 Watts per meter-kelvin, for example, metal.

8. Stabilization method according to any one of the preceding claims wherein the first thermal probe (S210) is, during the measurement steps, in contact: - Directly with the wall, or - Indirectly with the wall via a thermal bridge.

9. Stabilization method according to the preceding claim wherein the first thermal probe (S210) or the thermal bridge is fixed relative to the rod, during the assembly steps.

10. Stabilization method according to any one of the preceding claims, taken in dependence on claim 5, wherein, during the assembly steps, there is a clearance (J200) between the wall and an outer surface of the rod (T200) over at least 80% of a length of the rod (T200).

11. Stabilization method according to the preceding claim, in in which the first thermal probe (S210) protrudes from the outer surface of the rod (T200), during the measurement steps.

12. Soil stabilization system (SOL1) comprising: A delivery device capable of implementing the delivery steps of the stabilization process according to any one of the preceding claims and comprising the first tube (100, 100'), A measuring device capable of implementing the measurement steps of the stabilization process according to any one of the preceding claims, comprising the second tube (200) and the support (supl).

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