CN114134947B - Safety monitoring method for building foundation pile in saline environment - Google Patents
Safety monitoring method for building foundation pile in saline environment Download PDFInfo
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- CN114134947B CN114134947B CN202111498892.9A CN202111498892A CN114134947B CN 114134947 B CN114134947 B CN 114134947B CN 202111498892 A CN202111498892 A CN 202111498892A CN 114134947 B CN114134947 B CN 114134947B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/10—Deep foundations
- E02D27/12—Pile foundations
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
- G08B21/24—Reminder alarms, e.g. anti-loss alarms
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2600/00—Miscellaneous
- E02D2600/10—Miscellaneous comprising sensor means
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Abstract
The invention discloses a safety monitoring method for a building foundation pile in a saline environment, which is characterized in that a stress sensor is buried in a concrete structure forming the building foundation pile, the expansion force of crystallization generated by sulfate reaction at the front end of a crack of the concrete structure is detected by the stress sensor to judge the corrosion depth of sulfate, and an alarm is given when the corrosion depth reaches an alarm line. The method has the advantages of simple and feasible implementation, high monitoring reliability and strong practicability, and can better monitor the safety of the building foundation pile under the condition of being corroded by sulfate in a saline environment.
Description
Technical Field
The invention relates to the technical field of building structure safety monitoring, in particular to a safety monitoring method for a building foundation pile in a saline environment.
Background
Foundation piles are supporting foundations for load-bearing buildings, usually referred to as monopiles in a grouted foundation, generally made of a cement concrete structure. Therefore, the structural strength of the foundation pile has a fundamental influence on the building safety. And the concrete structure of the foundation pile can be damaged by sulfate erosion in the environments of seawater, saline-alkali soil, acid rain and the like, and the strength is reduced. In the environment that sulfate exists, after concrete is corroded or is subjected to pressure change to generate cracks, the sulfate invades into the concrete along with the cracks, then calcium hydroxide in the cracks and cement reacts with calcium aluminate hydrate to generate ettringite crystals, the volume of the ettringite crystals expands to about 100%, the cracks are propped up due to the generated ettringite crystals, the cracks are further enlarged and grown, the sulfate can invade to a deeper position, and the strength of a concrete structure is rapidly reduced due to vicious circle. And the strength of the foundation pile is reduced, so that the safety of the building is directly influenced. Therefore, for buildings in a saline environment, it is necessary to monitor the structural strength change of the foundation pile structure caused by the corrosion of sulfate so as to improve the safety of the building.
CN111310360A discloses a method for transmission and evaluation of concrete damage under sulfate erosion in a splash zone, which can predict the concrete damage under sulfate erosion in a splash zone of a marine environment, thereby providing a basis for durability analysis of a concrete structure. However, the method obtains the evaluation result by a theoretical analysis and calculation mode, and has low uncertainty and poor practicability.
Therefore, how to better monitor the safety of the building foundation piles under the condition of being corroded by sulfate in the saline environment becomes a method to be considered by the technical personnel in the field.
Disclosure of Invention
Aiming at the defects of the prior art, the technical problems to be solved by the invention are as follows: the method for monitoring the safety of the foundation pile of the building in the saline environment has the advantages of being simple to implement, high in monitoring reliability, high in practicability and capable of better monitoring the safety of the foundation pile of the building in the saline environment under the condition that the foundation pile of the building is corroded by sulfate.
In order to solve the technical problems, the invention adopts the following technical scheme:
a safety monitoring method for foundation piles of buildings in salinized environments is characterized in that a stress sensor is buried in a concrete structure forming the foundation piles of the buildings, the expansion force of crystals generated by sulfate reaction at the front ends of cracks of the concrete structure is detected through the stress sensor, the sulfate erosion depth is judged, and an alarm is given when the erosion depth reaches an alarm line.
This is because the destruction of the concrete structure by attack of sulfate is effected in such a way that, after a crack has been produced in the concrete structure, the water vapour entrained with sulfate ions naturally collects there and forms a small reaction bath, because of the narrowest point at the foremost end of the crack. So that the sulfate can react with calcium hydroxide and hydrated calcium aluminate mixed in the reaction tank and concrete to generate ettringite crystals, and after the crystals are generated, the crystals can form large expansion and further expand and extend the cracks, so that the cracks are gradually deepened after circulation. The applicant has considered that a forward positive pressure is generated when the crystals formed in the crack expand, and can determine the depth of the crack by detecting the pressure. Therefore, when the stress sensor buried at the preset depth position detects that the depth of the crack reaches the depth position, an alarm signal can be sent out to give an alarm to remind a foundation pile of being repaired or replaced, and building safety monitoring is achieved. Therefore, the device has the advantages of convenience, rapidness, reliability and the like.
Furthermore, a detection member is arranged beside the concrete foundation pile to be monitored, the detection member is made of the same concrete material as the concrete foundation pile, and the stress sensor is embedded in the detection member.
As described above, the concrete structure constituting the foundation pile of the building refers to a structure of a detection member. The stress sensor is buried in the foundation pile, and the structural strength of the foundation pile cannot be influenced by the existence of the stress sensor.
Furthermore, the detection member is a strip-shaped member which is arranged in parallel with the concrete foundation pile to be monitored and has the same cross section shape in the width direction, and both ends of the detection member in the height direction are pre-applied with simulation loads.
Therefore, the simulation load is pre-applied to the detection member according to the load borne by the concrete foundation pile to be monitored, so that the concrete foundation pile and the detection member bear the same load, and the crack generation rate and the crack growth rate of the concrete foundation pile and the detection member can be kept consistent under the condition that the material structure and the cross section of the concrete foundation pile are the same. The monitoring condition of the crack erosion depth of the detection member can better reflect the actual condition of the concrete foundation pile to be monitored. Therefore, on the premise of not influencing the strength of the concrete foundation pile to be monitored, the monitoring of the corroded depth of the concrete foundation pile is skillfully realized, and the monitoring reliability is ensured.
Further, the stress sensor is implemented by a strain gauge. In this way, by embedding the strain gauge in the detection member, the expansion force of the crystal generated by the sulfate reaction at the crack front end of the concrete structure is converted into the pressure against the strain gauge by the strain gauge, and the sulfate erosion depth is detected. The installation is conveniently implemented and the stress can be better monitored.
Further, the method is realized by adopting the following building foundation pile safety monitoring system, the building foundation pile safety monitoring system comprises a detection member which is arranged in parallel with the concrete foundation pile to be monitored, the detection member is made of the same concrete material as the concrete foundation pile, a strain gauge is embedded in the detection member at the monitoring depth position, the strain gauge is connected out of the detection member through a connecting wire embedded in the detection member and is connected with a control device, and the control device is connected with an alarm device.
Therefore, the erosion condition of the concrete foundation pile to be monitored is simulated and reflected through the detection member, when the detection member generates cracks and is eroded to the monitoring depth, the strain gauge is used for detecting the forward expansive force formed by the ettringite crystal expansion at the front end of the cracks, and a signal is given out to trigger the alarm device to give an alarm through the control device. Therefore, the monitoring and the alarming of the corrosion degree inside the concrete foundation pile can be realized under the condition that the strength of the concrete foundation pile to be monitored is not influenced, people can repair and maintain the concrete foundation pile in time conveniently, and the safety of the building is improved. The alarm device can be an alarm, a flash lamp or a signal transmitter, and the signal transmitter can transmit an alarm signal for the mobile terminal, so that remote monitoring is facilitated, but the alarm device is a mature prior art and is not described in detail herein.
Furthermore, the detection member is a long-strip-shaped member which is arranged in parallel with the concrete foundation pile to be monitored and has the same cross section shape in the width direction, and load loading devices are arranged at two ends of the detection member in the height direction and used for loading simulation loads on the detection member in the height direction.
Like this, can conveniently be according to waiting to monitor the concrete foundation pile load size that receives to detect with component simulation load in advance for the two bear the same load size, under the condition that self material structure and cross section are all the same, make the two produce the crackle and the crackle growth rate can keep unanimous. The monitoring condition of the crack erosion depth of the detection member can better reflect the actual condition of the concrete foundation pile to be monitored. The monitoring accuracy and reliability are better ensured.
Furthermore, the load loading device comprises two pressure plates which are pressed on the upper end and the lower end of the detection member, the peripheral width of each pressure plate exceeds the width of the detection member, a circle of through holes are uniformly distributed in each pressure plate, a pull rod penetrates through the through hole which is opposite to the position between the two pressure plates, the position of the pull rod, close to the end, is a threaded section, and a tensioning nut is screwed on the part penetrating through the pressure plates.
Therefore, by means of the matching of the tensioning nut and the pull rod, the axial compression load can be conveniently and quickly applied to the detection member, the magnitude of the load force can be conveniently adjusted, and the magnitude of the load force is consistent with the actual load of the concrete foundation pile to be monitored.
Further, the pull rod is made of spring steel materials.
The pull rod can better generate tensile force to form load and can better ensure the lasting effect of the load.
Furthermore, a pressure detection sensor for detecting the load is arranged between the pressure plate and the detection member, and the pressure detection sensor is connected with the control device.
Therefore, the change of the load can be detected, and the pressure on the detection member and the pressure on the concrete foundation pile to be monitored are ensured to be consistent by timely adjustment. The pressure borne by the concrete foundation pile to be monitored can be obtained by means of evaluation calculation or actual detection by arranging a pressure detection sensor at the root or the top of the foundation pile in advance.
Furthermore, the detection member is fixed on the concrete foundation pile to be monitored through a hoop. This facilitates the fixing.
Further, the strain gauge is disposed in parallel to the detection surface of the detection member.
Therefore, the expansion force of the crystal generated by the sulfate reaction at the front end of the crack can be better converted into the pressure right facing the strain gauge, the detection is realized, and the detection reliability of the strain gauge is improved.
Furthermore, a plurality of groups of strain gauges are embedded in the detection member to be detected at different depth positions.
In this way, alarms of different levels of risk can be implemented. The building safety is better improved.
Furthermore, the inner side of the strain gauge is fixedly arranged on a supporting frame of a rectangular frame structure made of hard materials.
Therefore, the strain gauge is convenient to mount and protect, and when the strain gauge is stressed to be detected, the supporting frame is convenient to bear the force to enable the strain gauge to be detected.
Furthermore, the supporting frame is provided with a plurality of coaxial and interval of equidimensions, and each group of foil gage is installed respectively on the supporting frame of equidimension.
Therefore, detection of different depths of each group of strain gauges is facilitated.
Furthermore, the outer surface of the supporting frame is provided with a strain gauge mounting groove, the depth of the strain gauge mounting groove is consistent with the thickness of the strain gauge, and the strain gauge is mounted in the mounting groove.
In this way, the strain gage is conveniently and better mounted and protected. When the device is implemented, the outer surface of the supporting frame is also provided with a wiring groove and used for arranging connecting wires.
Furthermore, the outer surface of the strain gauge is also provided with a layer of net-shaped framework, and the meshes of the net-shaped framework are smaller than the size of the minimum aggregate of the detection member.
Therefore, the mesh framework can protect the strain gauge in the production process of the detection member and avoid being worn out by aggregate and concrete. More importantly, in the monitoring process, when the front end of the crack reaches the position of the strain gauge, the front end of the crack is firstly contacted and acted on the reticular framework, and because the reticular framework is made of hard materials, the expanding force which is generated in the crack generation process and cracks towards two sides can be well shielded, the influence of the expanding force on the strain gauge is avoided, the strain gauge only bears the forward pressure generated by the crystal expansion of the front end of the crack, and the monitoring and detection can be better realized; meanwhile, the front end of the crack is restrained by the net-shaped framework due to expansion of two sides, so that the pressure of the crystal expansion in the forward direction is higher, and the reaction sensitivity of strain gauge detection is improved well.
Further, the net-shaped framework is a steel wire mesh.
Thus, it is made to have sufficient hardness to achieve the above effects better.
Furthermore, the whole reticular framework is of a rectangular framework structure and is sleeved outside the supporting framework.
Thus, the installation is convenient and the protection effect is improved.
Furthermore, the outer surface of the strain gauge is also provided with a layer of isolating membrane made of elastic material in an attaching mode.
Therefore, the isolating membrane can better protect the strain gauge from concrete corrosion in the production process of the test piece. And more importantly, the existence of the isolating film enables the front end of the crack to only extend to the isolating film, and the isolating film has elasticity, so that when the crack expands, a part of expansion force acting on the strain gauge through the net-shaped framework can act on the isolating film and is counteracted by the elasticity of the isolating film; therefore, the influence of the force of the crack expanding towards two sides on the strain gauge is further better avoided, and the strain gauge only bears the forward expansion force so as to better realize detection. Meanwhile, when the front end of the crack reaches the position of the strain gauge due to the elasticity of the isolating film, the isolating film can be spread to form a certain gap, so that the effect of crystal expansion in the crack can be forward applied to the strain gauge, and the situation that the strain gauge cannot bear force due to the fact that the crack cannot be completely spread is avoided. In practice, the isolation film is positioned between the website framework and the strain gauge. As seen from the principle process, the isolation film and the net-shaped framework exist simultaneously, so that not only can expansion force of cracks towards two sides be better prevented from acting on the strain gauge, but also the two can make up respective defects exactly, the strain gauge can be better protected, and the detection effect of the strain gauge can be improved. When the device is implemented, the periphery of the isolation film is sealed and fixed on the supporting frame, and the isolation film and the strain gauge can be freely arranged in a sliding mode. It is ensured that the above-mentioned effects of the barrier film can be achieved better.
In conclusion, the method has the advantages of simple and feasible implementation, high monitoring reliability and strong practicability, and can better monitor the safety of the building foundation pile in the saline environment under the condition of being corroded by sulfate.
Drawings
Fig. 1 is a schematic structural diagram of a safety monitoring system for foundation piles of a building according to an embodiment of the present invention.
Fig. 2 is a schematic view of the load applying apparatus of fig. 1 after its removal.
Fig. 3 is a cross-sectional view of the individual detecting member of fig. 2.
Fig. 4 is an enlarged view of the individual strain gauges at the circle positions in fig. 3.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments.
The specific implementation mode is as follows:
a safety monitoring method for foundation piles of buildings in salinized environment is characterized in that a stress sensor is buried in a concrete structure forming the foundation piles of the buildings, the expansion force of crystals generated by sulfate reaction at the front ends of cracks of the concrete structure is detected through the stress sensor to judge the corrosion depth of sulfate, and an alarm is given when the corrosion depth reaches an alarm line.
This is because the destruction of the concrete structure by attack of sulfate is effected in such a way that, after a crack has been produced in the concrete structure, the water vapour entrained with sulfate ions naturally collects there and forms a small reaction bath, because of the narrowest point at the foremost end of the crack. So that the sulfate can react with calcium hydroxide and hydrated calcium aluminate mixed in the concrete in the reaction solution tank to generate ettringite crystals, and after the crystals are generated, the crystals can form large expansion and further expand and extend cracks inwards, and the cracks are gradually deepened by the circulation. The applicant has considered that a forward positive pressure is generated when the crystals formed in the crack expand, and can determine the depth of the crack by detecting the pressure. Therefore, when the stress sensor buried at the preset depth position detects that the depth of the crack reaches the depth position, an alarm signal can be sent out to give an alarm to remind a foundation pile of being repaired or replaced, and building safety monitoring is achieved. Therefore, the device has the advantages of convenience, rapidness, reliability and the like.
The stress sensor is embedded in the detection member.
As described above, the concrete structure constituting the foundation pile of the building refers to a structure of a detection member. The stress sensor is buried in the foundation pile, and the structural strength of the foundation pile cannot be influenced by the existence of the stress sensor.
The detection member is a strip-shaped member which is arranged in parallel with the concrete foundation pile to be monitored and has the same cross section shape in the width direction, and simulation loads are pre-applied to two ends of the detection member in the height direction.
Therefore, the simulation load is pre-applied to the detection member according to the load borne by the concrete foundation pile to be monitored, so that the concrete foundation pile and the detection member bear the same load, and the crack generation rate and the crack growth rate of the concrete foundation pile and the detection member can be kept consistent under the condition that the material structure and the cross section of the concrete foundation pile are the same. The monitoring condition of the crack erosion depth of the detection member can better reflect the actual condition of the concrete foundation pile to be monitored. Therefore, on the premise of not influencing the strength of the concrete foundation pile to be monitored, the monitoring of the corroded depth of the concrete foundation pile is skillfully realized, and the monitoring reliability is ensured.
Wherein the stress sensor is realized by a strain gauge. In this way, by embedding the strain gauge in the detection member, the expansion force of the crystal generated by the sulfate reaction at the crack front end of the concrete structure is converted into the pressure against the strain gauge by the strain gauge, and the sulfate erosion depth is detected. The installation is conveniently implemented and the stress can be better monitored.
More specifically, the present embodiment is implemented by using the building foundation pile safety monitoring system shown in fig. 1 to 4, which includes a detecting member 1 disposed in parallel with a concrete foundation pile 6 to be monitored, the detecting member 1 is made of the same concrete material as the concrete foundation pile, a strain gauge 2 is embedded in the detecting member 1 at a monitoring depth position, the strain gauge 2 is connected to the detecting member 1 through a connecting wire 3 embedded in the detecting member and connected to a control device 4, and the control device 4 is connected to an alarm device 5.
In this way, the erosion condition of the concrete foundation pile to be monitored is simulated and reflected by the detection member, when the detection member generates a crack 24 and is eroded to the monitoring depth, the strain gauge detects the forward expansion force formed by the expansion of the ettringite crystal 25 at the front end of the crack 24, and a signal is given to trigger the alarm device to give an alarm through the control device. Therefore, the monitoring and the alarming of the corrosion degree inside the concrete foundation pile can be realized under the condition that the strength of the concrete foundation pile to be monitored is not influenced, people can repair and maintain the concrete foundation pile in time conveniently, and the safety of the building is improved. The alarm device can be an alarm, a flash lamp or a signal transmitter, and the signal transmitter can transmit an alarm signal for the mobile terminal, so that remote monitoring is facilitated, but the alarm device is a mature prior art and is not described in detail herein.
The detection member 1 is a strip-shaped member which is arranged in parallel with the concrete foundation pile 6 to be monitored, the cross section of the detection member in the width direction is consistent in shape, and load loading devices are mounted at two ends of the detection member 1 in the height direction and used for loading simulation loads on the detection member in the height direction.
Like this, can conveniently be according to waiting to monitor the concrete foundation pile load size that receives to detect with component simulation load in advance for the two bear the same load size, under the condition that self material structure and cross section are all the same, make the two produce the crackle and the crackle growth rate can keep unanimous. The monitoring condition of the crack erosion depth of the detection member can better reflect the actual condition of the concrete foundation pile to be monitored. The monitoring accuracy and reliability are better ensured.
The load loading device comprises two pressure plates 7 which are pressed on the upper end and the lower end of the detection component, the peripheral width of each pressure plate 7 exceeds the width of the detection component, a circle of through holes are uniformly distributed in each pressure plate, a pull rod 8 penetrates through each through hole which is opposite to the corresponding pressure plate, the position, close to the end part, of each pull rod 8 is a threaded section, and a tensioning nut 9 is screwed on the part penetrating out of each pressure plate.
Like this, rely on the cooperation of tie nut and pull rod, can convenient and fast ground for measuring exert the axial for the component and compress tightly load to can conveniently adjust the size of this loading force, make it and wait to monitor concrete foundation pile receive the actual load size unanimity.
Wherein, the pull rod 8 is made of spring steel material.
The pull rod can better generate a tensile force to form a load and can better ensure the lasting effect of the load.
A pressure detection sensor (not shown in the figure) for detecting the magnitude of the load is further arranged between the pressure plate 7 and the detection member 1, and the pressure detection sensor is connected with the control device.
Therefore, the change of the load can be detected, and the pressure on the detection member and the pressure on the concrete foundation pile to be monitored are ensured to be consistent by timely adjustment. The pressure borne by the concrete foundation pile to be monitored can be obtained by means of evaluation calculation or actual detection by arranging a pressure detection sensor at the root or the top of the foundation pile in advance.
Wherein, the detection member 1 is fixed on the concrete foundation pile 6 to be monitored through the anchor ear 10. This facilitates the fixing.
Wherein the strain gauge 2 is disposed parallel to the detection member detection surface.
Therefore, the expansion force of the crystals generated by the sulfate reaction at the front ends of the cracks can be better converted into the pressure right facing the strain gauge, the detection is realized, and the detection reliability of the strain gauge is improved.
Wherein, a plurality of groups of strain gauges 2 are embedded in different depth positions in the member 1 for detection to be detected.
In this way, a graduated warning of different levels of risk can be achieved. The building safety is better improved.
Wherein, the inner side of the strain gauge 2 is fixed on a supporting frame 20 of a rectangular frame structure made of hard materials.
Like this, conveniently realize the installation and the protection to the foil gage, during the foil gage atress was examined, braced frame made things convenient for the load to make its realization detect.
The supporting frame 20 is provided with a plurality of coaxial strain gauges at intervals, and the strain gauges are respectively mounted on the supporting frames 20 with different sizes.
Therefore, detection of different depths of each group of strain gauges is facilitated.
Wherein, braced frame surface is provided with foil gage mounting groove 21, and foil gage mounting groove 21 degree of depth is unanimous with foil gage thickness, and the foil gage is installed in the mounting groove.
Thus, the strain gauge is convenient and better to install and protect. When the device is implemented, the outer surface of the supporting frame is also provided with a wiring groove and used for arranging connecting wires.
Wherein, the outer surface of the strain gauge is also provided with a layer of net-shaped framework 22, and the meshes of the net-shaped framework 22 are smaller than the size of the minimum aggregate of the detection member.
Therefore, the mesh framework can protect the strain gauge in the production process of the detection member and avoid being worn out by aggregate and concrete. More importantly, in the monitoring process, when the front end of the crack reaches the position of the strain gauge, the front end of the crack is firstly contacted and acted on the reticular framework, and because the reticular framework is made of hard materials, the expanding force which is generated in the crack generation process and cracks towards two sides can be well shielded, the influence of the expanding force on the strain gauge is avoided, the strain gauge only bears the forward pressure generated by the crystal expansion of the front end of the crack, and the monitoring and detection can be better realized; meanwhile, the front end of the crack is restrained by the net-shaped framework due to expansion of the two sides, so that the pressure of the crystal expansion in the forward direction is larger, and the reaction sensitivity of strain gauge detection is improved well.
Wherein, the net-shaped framework 22 is a steel wire net.
Thus, it is made to have sufficient hardness to achieve the above effects better.
Wherein, the net-shaped framework 22 is a rectangular framework structure and is sleeved outside the supporting framework 20.
Thus, the installation is convenient and the protection effect is improved.
Wherein, the outer surface of the strain gauge 2 is also provided with a layer of isolation film 23 made of elastic material in an attaching way.
In this way, the isolating membrane can not only better protect the strain gauge from concrete corrosion during the production process of the test piece. And more importantly, the existence of the isolating film enables the front end of the crack 24 to only extend to the isolating film, and the isolating film has elasticity, so that when the crack expands, a part of expansion force acting on the strain gauge through the net-shaped framework can act on the isolating film and be counteracted by the elasticity of the isolating film; therefore, the influence of the force of the crack expanding towards two sides on the strain gauge is further better avoided, and the strain gauge only bears the forward expansion force so as to better realize detection. Meanwhile, when the front end of the crack reaches the position of the strain gauge due to the elasticity of the isolating film, the isolating film can be spread to form a certain gap, so that the effect of crystal expansion in the crack can be forward applied to the strain gauge, and the situation that the strain gauge cannot bear force due to the fact that the crack cannot be completely spread is avoided. The isolation film is positioned between the website framework and the strain gauge when in implementation. As can be seen from the principle and process, the isolation film and the reticular skeleton exist simultaneously, so that not only can the expansion force from the crack to the two sides be better prevented from acting on the strain gauge, but also the two can make up respective defects exactly, the strain gauge can be better protected, and the detection effect of the strain gauge can be improved. When the device is implemented, the periphery of the isolation film is sealed and fixed on the supporting frame, and the isolation film and the strain gauge can be freely arranged in a sliding mode. It is ensured that the above-mentioned effects of the barrier film can be achieved better.
Claims (7)
1. A safety monitoring method for a foundation pile of a building in a salinized environment is characterized in that a detecting member is fixedly arranged beside a concrete foundation pile to be monitored, the detecting member is made of the same concrete material as the concrete foundation pile to be monitored, a stress sensor is embedded in the detecting member, the sulfate erosion depth is judged by detecting the expansive force of crystallization generated by sulfate reaction at the front end of a crack of a concrete structure through the stress sensor, and an alarm is given when the erosion depth reaches an alarm line; the detection member is a strip-shaped member which is arranged in parallel with the concrete foundation pile to be monitored and has a cross section with the same shape in the width direction, and simulation loads are pre-applied to two ends of the detection member in the height direction; the two ends of the detection member in the height direction are provided with load loading devices, and the load loading devices are used for loading simulation loads on the detection member in the height direction; the load loading device comprises two pressure plates which are in compression joint with the upper end and the lower end of the detection member, the peripheral width of each pressure plate exceeds the width of the detection member, a circle of through holes are uniformly distributed in each pressure plate, a pull rod penetrates through the through hole which is opposite to the position between the two pressure plates, the position, close to the end part, of the pull rod is a threaded section, and a tensioning nut is screwed on the part penetrating through the pressure plates.
2. The method for monitoring the safety of the foundation piles of the buildings in the saline environment as claimed in claim 1, wherein the stress sensors are implemented by strain gauges.
3. The method for monitoring the safety of the foundation piles of the buildings in the saline-alkaline environment as claimed in claim 1, wherein the monitoring method is implemented by a system for monitoring the safety of the foundation piles of the buildings, the system for monitoring the safety of the foundation piles of the buildings comprises a detection member which is arranged in parallel with the concrete foundation piles to be monitored, the detection member is made of the same concrete material as the concrete foundation piles to be monitored, a strain gauge is embedded in the detection member at the monitoring depth position, the strain gauge is connected out of the detection member through a connecting wire embedded in the detection member and is connected with a control device, and the control device is connected with an alarm device.
4. The method for monitoring the safety of the foundation piles of the buildings in the saline environment as claimed in claim 3, wherein a pressure sensor for detecting the magnitude of the load is further arranged between the pressing plate and the detecting member, and the pressure sensor is connected with the control device;
the pull rod is made of spring steel material;
the detection member is fixed on the concrete foundation pile to be monitored through the hoop.
5. The method for monitoring the safety of foundation piles of buildings in saline environments as claimed in claim 3, wherein the strain gauge is arranged parallel to the detection surface of the detection member;
a plurality of groups of strain gauges are embedded in the component to be detected at different depth positions;
the inner side of the strain gauge is fixedly arranged on a support frame of a rectangular frame structure made of hard materials;
the supporting frames are coaxial and are provided with a plurality of strain gauges in different sizes at intervals, and each group of strain gauges is respectively arranged on the supporting frames in different sizes;
the braced frame surface is provided with the foil gage mounting groove, and foil gage mounting groove degree of depth and foil gage thickness are unanimous, and the foil gage is installed in the mounting groove.
6. The method for monitoring the safety of the foundation pile of the building in the saline environment as claimed in claim 5, wherein a layer of net-shaped framework is further arranged on the outer surface of the strain gauge, and the meshes of the net-shaped framework are smaller than the size of the minimum aggregate of the detection member;
the net-shaped framework is a steel wire mesh;
the whole reticular framework is of a rectangular framework structure and is sleeved outside the supporting framework.
7. The method for monitoring the safety of the foundation piles of the buildings in the saline environment as claimed in claim 5, wherein the outer surface of the strain gauge is further provided with a layer of isolation film made of elastic material.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310076189.1A CN116043928A (en) | 2021-12-09 | 2021-12-09 | Building foundation pile safety monitoring system |
| CN202111498892.9A CN114134947B (en) | 2021-12-09 | 2021-12-09 | Safety monitoring method for building foundation pile in saline environment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111498892.9A CN114134947B (en) | 2021-12-09 | 2021-12-09 | Safety monitoring method for building foundation pile in saline environment |
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