CN117740246A - Leakage monitoring method and system applied to underground diaphragm wall structure - Google Patents

Abstract

The invention discloses a leakage monitoring method applied to an underground diaphragm wall structure, which comprises the following steps: a sensing optical cable circuit is laid on the underground continuous wall structure by utilizing a self-heating fiber Bragg grating temperature sensor, so as to construct a distributed fiber monitoring network; demodulating and measuring a self-heating fiber Bragg grating temperature sensor through a fiber regulator and a field host, and collecting sensing data of a distributed fiber monitoring network; establishing a communication channel to realize data transmission and interaction; carrying out data analysis on the sensing data of the distributed optical fiber monitoring network to obtain an analysis result of the penetration information of the underground continuous wall structure; and (5) completing the security decision making. The technical scheme enhances the sensitivity of seepage field monitoring, can more differentially measure seepage and the water flow speed of seepage, and completes the temperature measurement of the space in a certain range of key parts of the structure. The system monitoring device can realize long-term and accurate system monitoring of seepage of the underground continuous wall structure.

Description

Leakage monitoring method and system applied to underground diaphragm wall structure

Technical Field

The invention relates to the technical field of foundation pit engineering monitoring, in particular to a leakage monitoring method and system applied to an underground diaphragm wall structure.

Background

In the development and utilization of underground space, more and more foundation pit engineering faces the problems of large excavation depth, high requirements on surrounding environment protection, narrow construction space and the like. In many supporting structures of foundation pit engineering, underground continuous walls are widely used due to high rigidity, good continuity and high safety coefficient. The underground continuous wall is formed by using special grooving machine and slurry protection wall at specific position, digging deep groove with a certain length (generally 4-6 m, unit groove section), inserting reinforcement cage, pouring concrete in the deep groove filled with slurry by using conduit method, and finally connecting groove sections with each other by using special joint to form an integral supporting structure. Therefore, the process of joint connection affects the protection effect of the underground diaphragm wall, if the mud and sand are mixed in the joint, the joint connection is not firm, and leakage is likely to occur. The harm of leakage in the foundation pit construction process mainly comprises flowing sand, piping and gushing. In order to ensure engineering safety, the groundwater state of the heavy point part of the underground continuous wall needs to be monitored during construction. Through leakage monitoring, the underground water state behind the ground wall back can be accurately known, the state of the key part of the structure is known, and the method has important significance for supporting stable structure and construction safety of foundation pit engineering.

At present, in the technical field of foundation pit engineering monitoring, in particular to a technical method related to underground continuous wall leakage monitoring, mainly comprises a natural electric field method, a resistivity method, an ultrasonic three-dimensional imaging technology, a ground penetrating radar, a high-density electric method, a transient electromagnetic method and the like. The technical methods have the characteristics of point measurement, so that the omnibearing monitoring of the measured object is difficult to realize, and the sensors are mostly resistive, piezoresistive and capacitive, are easy to corrode, and are difficult to realize long-term monitoring. Most of conventional monitoring technologies still cannot realize real-time monitoring, and the sensing principles are various, the data types are many, and a large-scale real-time monitoring system is difficult to integrate.

Therefore, how to design a leakage monitoring method and system applied to an underground diaphragm wall structure, and to realize long-term and accurate system monitoring of seepage of the underground diaphragm wall structure is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a leakage monitoring method and system applied to an underground diaphragm wall structure, wherein a plurality of fiber Bragg grating sensors are connected in series through an optical cable to form a distributed fiber Bragg grating temperature measuring circuit, so that temperature measurement of a space in a certain range of key parts of a structure body can be realized.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

in a first aspect, the present invention provides a leak monitoring method for an underground diaphragm wall structure, comprising:

step one: a sensing optical cable circuit is laid on the underground continuous wall structure by utilizing a self-heating fiber Bragg grating temperature sensor, so as to construct a distributed fiber monitoring network;

step two: demodulating and measuring a self-heating fiber Bragg grating temperature sensor through a fiber regulator and a field host, and collecting sensing data of a distributed fiber monitoring network;

step three: establishing a communication channel, and transmitting sensing data of the distributed optical fiber monitoring network to a remote host to realize data transmission and interaction;

step four: carrying out data analysis on the sensing data of the distributed optical fiber monitoring network to obtain an analysis result of the penetration information of the underground continuous wall structure;

step five: and according to the analysis result of the permeability information of the underground continuous wall structure, completing the safety decision making.

Preferably, in the first step, a distributed optical fiber monitoring network is constructed, including: the self-heating fiber Bragg grating temperature sensor and the main ribs are bound and laid on the top, the bottom or the inner surface and the outer surface of the surface layer of the reinforcement cage structure of the underground continuous wall, and are arranged in a grid mode.

Preferably, the self-heating fiber Bragg grating temperature sensor adopts a PID controller to carry out closed-loop control on the self-heating temperature.

Preferably, in the fourth step, the data analysis is performed on the sensing data of the distributed optical fiber monitoring network, including:

performing numerical simulation processing on the sensing data by using auxiliary software and hardware;

completing wavelet analysis, quantitative analysis, data characterization processing and data network processing of the sensing data based on a database;

performing secondary analysis and raw data processing with the aid of leakage information, the leakage information comprising: assistance information, location information, spatial positioning and evaluation criteria.

Preferably, in the fifth step, according to the analysis result of the infiltration information of the underground continuous wall structure, a security decision making is completed, and the security decision includes an early warning processing decision, a dangerous alarm processing decision, a security evaluation processing decision, and a disaster coping mode.

In a second aspect, a leak monitoring system for use in a subterranean continuous wall structure, comprising:

the self-heating optical fiber Bragg grating temperature sensor, the data acquisition equipment and the remote host;

the self-heating fiber Bragg grating temperature sensor is utilized to lay a sensing optical cable circuit on the underground continuous wall structure, a distributed fiber monitoring network is constructed, and key leakage monitoring of the underground continuous wall structure is realized;

the data acquisition equipment comprises an optical fiber regulator and a field host, is connected with a self-heating optical fiber Bragg grating temperature sensor through an optical fiber line, demodulates and measures the self-heating optical fiber Bragg grating temperature sensor, acquires sensing data of a distributed optical fiber monitoring network and transmits the sensing data to a remote host;

and the remote host analyzes and processes the sensing data based on the auxiliary software and hardware, the database and the penetration information unit, and finally completes the security decision making.

Compared with the prior art, the invention has the following beneficial effects:

1. the monitoring system and the monitoring method can monitor the temperature distribution of the concrete structures such as the underground diaphragm wall of the foundation pit structure for a long time and high precision, and can obtain the seepage distribution of the structure through further analysis, thereby comprehensively controlling the water field characteristics of key parts of the underground diaphragm wall structure in the construction period and the operation period;

2. the monitoring system has the advantages of simple installation and construction process, almost no interference to main engineering construction, corrosion resistance, electromagnetic interference resistance, large information quantity and the like, and can realize long-term monitoring;

3. the monitoring method of the invention not only can monitor the key parts of the structure, but also can arrange the sensors according to a certain density grid to monitor the temperature state of the structure in the corresponding area;

4. the monitoring system can be set by the demodulator to perform unmanned automatic monitoring and data acquisition, and can also be used for performing data acquisition, storage and transmission by controlling the demodulator through a network to realize remote monitoring.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a leak monitoring method for a subsurface continuous wall structure according to the present invention;

fig. 2 is a schematic diagram of a self-heating fiber bragg grating temperature sensor provided by the invention placed at the edge of a reinforcement cage;

fig. 3 is a schematic diagram of a self-heating fiber bragg grating temperature sensor provided by the invention in a position inside a reinforcement cage;

FIG. 4 is a schematic diagram of the installation and arrangement of the self-heating fiber Bragg grating temperature sensor provided by the invention;

FIG. 5 is a block diagram of a leak monitoring system for use in a subterranean wall structure in accordance with the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1:

as shown in fig. 1, the present embodiment provides a leakage monitoring method applied to an underground diaphragm wall structure, including:

step one: a sensing optical cable circuit is laid on the underground continuous wall structure by utilizing a self-heating fiber Bragg grating temperature sensor, so as to construct a distributed fiber monitoring network;

step two: demodulating and measuring a self-heating fiber Bragg grating temperature sensor through a fiber regulator and a field host, and collecting sensing data of a distributed fiber monitoring network;

step three: establishing a communication channel, and transmitting sensing data of a distributed optical fiber monitoring network to a remote host to realize data transmission and interaction;

step four: carrying out data analysis on the sensing data of the distributed optical fiber monitoring network to obtain an analysis result of the penetration information of the underground continuous wall structure;

step five: and according to the analysis result of the permeability information of the underground continuous wall structure, completing the safety decision making.

The technical scheme enhances the sensitivity of seepage field monitoring, can more differentially measure seepage and the water flow speed of seepage, and completes the temperature measurement of the space in a certain range of key parts of the structure. The system monitoring device can realize long-term and accurate system monitoring of seepage of the underground continuous wall structure.

Further, in order to better understand the technical solution of the present invention, the following further details are provided for describing the related principles of the above leakage monitoring method:

the self-heating fiber Bragg grating temperature sensor utilizes the photoinduced refractive index change of a photosensitive fiber to enable the photosensitive fiber to be close to a phase mask, and utilizes the space interference fringes generated by near field diffraction of the phase mask to form periodic change of refractive index in the fiber to form the fiber grating. The refractive index of the fiber grating is periodically distributed along the axial direction of the fiber, the fiber grating has good wavelength selection characteristics, incident light meeting the Bragg diffraction condition is coupled and reflected at the fiber Bragg grating, light with other wavelengths can completely pass through without being influenced, the reflection spectrum has the maximum value at the central wavelength of the fiber Bragg grating, and the variation of the temperature has good linear relation with the displacement of the central wavelength of the reflected light. By detecting the drift of the reflected light center wavelength, a temperature measurement can be achieved using a demodulation device. The fiber Bragg grating temperature sensor has the main advantages of high precision and good stability. A plurality of fiber Bragg grating sensors are connected in series through an optical cable to form a distributed fiber Bragg grating temperature measuring circuit, so that temperature measurement of a space in a certain range of key parts of a structural body can be realized.

In addition, since water leaks continuously carry away ambient heat during the flow, the change in heat can be obtained by measuring the temperature, which is closely related to the flow rate of the seepage. In order to measure leakage and the water flow speed of leakage more differently, a self-heating type fiber Bragg grating temperature sensor (constant current acts to generate heat with rated power) is adopted, and a temperature field is artificially superimposed on the sensor by electrifying and heating, so that an artificial temperature difference is generated between the sensor and a measured medium and between the sensor and a seepage field. When the heat taken away by seepage is equal to the heat of the self-heating sensor, the heat between the sensor and the surrounding concrete body reaches dynamic balance, and the temperature change value of the sensor tends to be a stable value. When the artificially generated temperature difference is obvious enough, the temperature of the to-be-measured point can be accurately measured by utilizing the fiber Bragg grating temperature measurement technology through high resolution, and is compared with the predicted temperature before heating, and the temperature change value is only related to the attribute of the sensor and the heating voltage power and is irrelevant to the surrounding environment. By the method, the temperature of the original environment is increased, obvious temperature difference is generated between the sensor and the surrounding environment, the sensitivity of seepage field monitoring is greatly enhanced, and the monitoring range and the accuracy are greatly improved.

The steps of the above embodiments are described in further detail below:

as shown in fig. 2 and 3, in a first step, a distributed optical fiber monitoring network is constructed, including: the self-heating fiber Bragg grating temperature sensor and the main ribs are bound and laid on the top, the bottom or the inner surface and the outer surface of the surface layer of the reinforcement cage structure of the underground diaphragm wall, and are arranged in a gridding way.

After the concrete pouring is completed, the self-heating fiber Bragg grating temperature sensor and the sensing optical cable are 5-10cm away from the concrete surface; when the self-heating fiber Bragg grating temperature sensor crosses the leakage area, the temperature is inevitably abnormal due to the fact that the heat conduction mode of the self-heating fiber Bragg grating temperature sensor is different from that of other places, so that the fiber Bragg wavelength can drift, the temperature change can be obtained by measuring the fiber Bragg grating temperature sensor, and the leakage condition is further identified.

And establishing a data acquisition station outside the foundation pit, and connecting the laid sensing optical cable line to the data acquisition station through an optical cable. Further, after the concrete pouring is completed and the hydration heat of the concrete is completely released and the concrete is initially set, collecting and monitoring an initial value; and then, collecting sensor data according to construction nodes in a concrete curing period and in each construction period, and utilizing temperature data measured by data collecting equipment to further obtain the leakage condition of the foundation pit engineering underground diaphragm wall structure in the construction period, thereby providing a basis for ensuring construction safety and guiding later construction.

In addition, the self-heating fiber Bragg grating temperature sensor is characterized in that a fiber grating is reinforced, a heat conducting material is added and packaged (generally a steel wire mesh or carbon fiber) to form a heatable sensing optical cable, and a direct-current stabilized power supply is arranged at one end of the sensing optical cable to heat the optical cable at a certain temperature.

The self-heating fiber Bragg grating temperature sensor adopts a PID controller to carry out closed-loop control on the self-heating temperature. The self-heating process of the fiber Bragg grating temperature sensor by adopting the PID controller can be divided into the following steps:

setting a target temperature value: the target temperature value to be maintained is first determined. The temperature value can be a preset constant or a dynamic value which changes with time;

acquiring a current temperature value: the current temperature value is measured by a fiber bragg grating temperature sensor. This value can be obtained in real time and updated as needed.

Calculating an error value: and comparing the target temperature value with the current temperature value, and calculating a deviation or error value. This value represents the difference between the current temperature and the target temperature.

Calculating PID controller output: based on the PID control algorithm, an output value of the PID controller is calculated from the error value. The PID control algorithm decomposes the error value into proportional, integral and derivative terms, and generates an output value by adjusting the weights and coefficients of these terms.

Adjusting self-heating current: the output value of the PID controller is used as a control signal of the self-heating current. The intensity and direction of the self-heating current are adjusted according to the magnitude and direction of the output value.

If the output value is positive, indicating that the current temperature is lower than the target temperature, the intensity of the self-heating current may be increased to increase the temperature. If the output value is negative, indicating that the current temperature is higher than the target temperature, the intensity of the self-heating current may be reduced to lower the temperature. If the output value is zero, indicating that the present temperature is close to the target temperature, the state of the self-heating current can be maintained.

And (3) cycle control: the above steps are performed in a continuous loop. The closed loop control of the temperature is realized by continuously measuring the current temperature, calculating an error value and adjusting the self-heating current according to the output of the PID controller. Thus, the temperature can stably run near the set value, and self-heating control of the temperature of the fiber Bragg grating is realized.

It should be noted that in practical applications, the selection and adjustment of PID parameters is also an important step. It is often necessary to test and debug according to the characteristics of the system to find suitable PID parameters so that the control process is more stable and accurate.

The mounting steps of the self-heating fiber bragg grating temperature sensor in the embodiment include:

(1) Laying marks: before concrete pouring, after the reinforcement mesh is paved, marking the distribution line of the sensing optical cable and the point positions of the sensors on the reinforcement mesh according to the design requirement of the monitoring scheme. In the marking process, the laying length of each section of the sensing optical cable needs to be measured, and the minimum curvature requirement of the sensing optical cable needs to be considered at the corner position.

(2) Sensor arrangement: according to the design, the sensor is arranged along the mark and is temporarily fixed by adhesive tape or a binding tape. During cable laying, the sensing optical cable is kept in a loose state, all optical cable lines are laid to the top of a foundation pit along structural steel bars, and a free length of 2-5m is reserved for line integration and welding jumper wires.

(3) Fixing before pouring: the transfer cable is fixed immediately before the concrete pouring operation is started. The fixing mode is to fix the optical cable on the reinforcing mesh point by adopting a high-strength PVC adhesive tape. The degree of density of the fixed points depends on whether the form of the sensing optical cable can be controlled, the sensing optical cable close to the two ends of the sensor is reinforced and fixed, the sensor is prevented from being shifted or damaged in the concrete pouring process, and the sensing optical cable is required to be linearly distributed along the marking line in the fixing process.

(4) Corner control and buffer protection: for the corner position, the minimum curvature radius requirement of the sensing optical cable is met, and the fixed point is encrypted when the sensing optical cable is laid and fixed, so that the position cannot move along with pouring construction. For the position which is easy to cause impact in pouring, a buffer layer can be formed by winding buffer materials such as foam sponge and the like so as to protect the sensing circuit from being damaged.

(5) Welding joints: after pouring construction is completed and welding operation conditions are met, welding operation is carried out on nodes to be welded according to a monitoring design scheme, a sensing network is formed, and the sensing network is connected into a transmission optical cable to form a monitoring system.

(6) Line protection: and corresponding protection measures are adopted for positions, such as welding nodes, high-risk sections and the like, which are easy to cause line damage according to specific conditions of actual monitoring objects and monitoring environments.

In the second step, as shown in fig. 4, the data acquisition device comprises a cabinet type multichannel fiber bragg grating demodulator, the measurement temperature range is-40-120 ℃, the resolution is +/-0.1 ℃, and the measurement accuracy is +/-0.5 ℃. The high precision of the demodulator is beneficial to realizing automatic remote monitoring and advanced monitoring and forecasting of structural leakage. Factors affecting temperature variation are mainly from two aspects: firstly, material heat conduction attribute factors from the reinforced concrete structure of the underground diaphragm wall; and secondly, factors from the outside, such as seepage, air temperature and the like. For underground diaphragm walls, the material heat conduction properties of the structure are basically unchanged or change little, so that the main factor for changing the temperature characteristic value is the characteristic of the water division field. Therefore, as long as a relation is established between the seepage and the temperature, the seepage can be reversely determined through the measured temperature, and the seepage is monitored.

The temperature T of the optical cable is in a linear function relation with the seepage rate V:

V＝k ₁ T+b ₁

wherein k is ₁ 、b ₁ Are all constant and can be measured by indoor calibration tests.

Establishing a communication channel, and transmitting sensing data of the distributed optical fiber monitoring network to a remote host to realize data transmission and interaction; in this embodiment the demodulator transmits the measurement results to a remote host for processing and analysis by digital communication.

In this embodiment, a Data technology based on Labview platform is adopted, and Data can be transmitted to a remote server end in the form of network Data packets through an ethernet network. After the data is transmitted to the remote server, the structured query language SQLServer is adopted to effectively manage the monitoring data, and a management database is newly built and accessed. The operation efficiency is greatly improved, and the data storage cost is reduced.

And fourthly, carrying out data analysis on sensing data of the distributed optical fiber monitoring network, after acquiring real-time seepage field monitoring data by a remote server, carrying out visual management, query, extraction and comparison on the monitoring data by adopting software technologies such as a GIS (geographic information system), a database and the like, automatically extracting characteristic points and abnormal points, then analyzing and processing the abnormal points by an analysis module or manually, carrying out numerical simulation and inversion by utilizing a calculation result, judging and identifying a seepage mode, evaluating the development trend of a seepage field, carrying out security evaluation on the monitored seepage field, and adopting corresponding processing measures.

Comprising the following steps:

performing numerical simulation processing on the sensing data by using auxiliary software and hardware; in terms of data processing, numerical modeling can help perform large-scale calculations, model the behavior of complex systems, and generate a large number of numerical results. Common numerical simulation software includes NumPy and SciPy among MATLAB, python. The auxiliary software and hardware can accelerate the processing of numerical simulation by providing higher computing performance and memory capacity, thereby reducing computing time and resource consumption.

Completing wavelet analysis, quantitative analysis, data characterization processing and data network processing of the sensing data based on the database;

wavelet analysis: wavelet analysis a mathematical method for processing non-stationary signals can decompose the signal into wavelet components of different frequencies. Frequency and time information of the signal can be obtained by storing and managing raw signal data in a database and analyzing and processing the signal using a wavelet analysis algorithm.

Quantitative analysis: the database may store various quantitative data and provide query and statistical functions to support quantitative analysis of the data.

Characterization of data: the database may characterize data as associations between entities and attributes by designing appropriate data table structures and relationships. By defining appropriate relationships and constraints, efficient management and querying of data characterizations can be achieved.

Data network processing: the database may store and manage topology and connection information of the data network.

Performing auxiliary analysis and original data processing by means of leakage information, wherein the leakage information comprises: assistance information, location information, spatial positioning and evaluation criteria.

Auxiliary information: some additional knowledge and background information is available through the leakage information and can be used to aid in the understanding and analysis of the raw data.

Evaluation criteria: the leakage information may provide information about the evaluation criteria and metrics to aid in formulating an evaluation method for data processing. By analyzing the evaluation criteria in the leakage information, suitable data processing metrics can be determined and the data evaluated and compared accordingly.

Spatial positioning: the leak information may contain information about the geographic location that may be used to geolocate the data. By correlating the location information in the leakage information with the data, processing and analysis of the geographic data may be achieved.

Position information: the location information in the leak information may be used to locate and identify the data. By using the location information, the data can be precisely located and distinguished for better analysis and processing.

And fifthly, completing safety decision making according to the analysis result of the infiltration information of the underground continuous wall structure, wherein the safety decision making comprises early warning processing decision, dangerous alarm processing decision, safety evaluation processing decision and disaster coping mode.

Early warning refers to timely warning related personnel and taking measures to prevent accidents after the potential safety hazard is possibly obtained through analysis of the infiltration information of the underground continuous wall structure. And analyzing and processing the monitoring data by utilizing big data and artificial intelligence technology. By establishing a corresponding model and algorithm, the penetration condition of the underground continuous wall structure can be detected, and an early warning signal can be sent out in advance. A complete early warning system is established, and the early warning system comprises various early warning signals such as sound, light, vibration and the like. When the analysis result of the monitoring data shows that potential safety hazards exist, the system can automatically trigger an early warning signal to remind workers to take measures in time.

A hazard warning refers to sending emergency warning signals to the relevant personnel to prompt them to take immediate emergency action when a severe penetration condition occurs in the underground diaphragm wall structure or an accident is likely to occur. Alarm devices such as fire alarms, smoke detectors, etc. are installed near the underground diaphragm wall structure. When the dangerous signal is detected, the alarm device can be automatically triggered to emit high-volume sound or flash signals. An emergency communication network is established, including telephone, intercom, wireless communication, etc. When a dangerous situation occurs, the relevant personnel can quickly contact and coordinate actions through the communication device.

The safety evaluation is to comprehensively evaluate the safety of the underground continuous wall structure to determine whether the underground continuous wall structure meets relevant safety standards and requirements. Continuously monitoring and detecting the underground continuous wall structure, and collecting and recording related data and parameters of the structure. By analyzing and comparing the monitoring data, the safety performance and state of the structure can be evaluated. And analyzing and evaluating the risk possibly existing in the underground continuous wall structure by using the risk evaluation model and method. By identifying and evaluating the risk, the security level of the structure and the corresponding measures to be taken can be determined.

The disaster response is to take corresponding preventive and emergency measures aiming at the disaster possibly occurring in the analysis result of the infiltration information of the underground diaphragm wall structure so as to reduce the possibility and influence of the accident. And (3) making and implementing an emergency plan of the underground diaphragm wall structure, and defining the responsibility and action plan of related personnel. The emergency treatment method comprises the steps of emergency treatment flow, emergency equipment preparation, personnel evacuation, rescue and the like.

The technical scheme of safety decision making for early warning, danger warning, safety evaluation and disaster coping should comprehensively use the technical means of monitoring systems, data analysis, early warning systems, alarm devices, emergency communication, structural monitoring, risk analysis, emergency plans and the like to ensure the safety of underground continuous wall structures and the capability of coping with emergencies.

Example 2:

as shown in fig. 5, a leakage monitoring system for use in a diaphragm wall structure, comprising:

the self-heating optical fiber Bragg grating temperature sensor, the data acquisition equipment and the remote host;

the self-heating fiber Bragg grating temperature sensor is utilized to lay a sensing optical cable circuit on the underground continuous wall structure, a distributed fiber monitoring network is constructed, and key leakage monitoring of the underground continuous wall structure is realized;

the data acquisition equipment comprises an optical fiber regulator and a field host, is connected with a self-heating optical fiber Bragg grating temperature sensor through an optical fiber line, demodulates and measures the self-heating optical fiber Bragg grating temperature sensor, acquires sensing data of a distributed optical fiber monitoring network and transmits the sensing data to a remote host;

and the remote host analyzes and processes the sensing data based on the auxiliary software and hardware, the database and the penetration information unit, and finally completes the security decision making.

Compared with the traditional underground continuous wall monitoring mode, the monitoring system and the monitoring method in the embodiment have the advantages that the installation and construction process is simple, the main engineering construction is almost free from interference, the sensor has the advantages of corrosion resistance, electromagnetic interference resistance, large information quantity and the like, and long-term monitoring can be realized.

The structure key position can be monitored, the sensors can be arranged according to a certain density grid, and the temperature state of the structure in the corresponding area can be monitored; the unmanned automatic monitoring and data acquisition can be carried out, and meanwhile, the data acquisition, storage and transmission can be carried out through a network control demodulator, so that the remote monitoring can be realized; the method can monitor the temperature distribution of the concrete structures such as the underground diaphragm wall of the foundation pit structure in a systematic, long-term and high-precision manner, and can obtain the seepage distribution of the structure through further analysis, thereby comprehensively controlling the water field characteristics of key positions of the underground diaphragm wall structure in the construction period and the operation period.

In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, so that the same or similar parts between the embodiments are referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A leak monitoring method for an underground diaphragm wall structure, comprising:

step one: a sensing optical cable circuit is laid on the underground continuous wall structure by utilizing a self-heating fiber Bragg grating temperature sensor, so as to construct a distributed fiber monitoring network;

step two: demodulating and measuring a self-heating fiber Bragg grating temperature sensor through a fiber regulator and a field host, and collecting sensing data of a distributed fiber monitoring network;

step three: establishing a communication channel, and transmitting sensing data of the distributed optical fiber monitoring network to a remote host to realize data transmission and interaction;

step four: carrying out data analysis on the sensing data of the distributed optical fiber monitoring network to obtain an analysis result of the penetration information of the underground continuous wall structure;

step five: and according to the analysis result of the permeability information of the underground continuous wall structure, completing the safety decision making.

2. The method for monitoring leakage applied to underground diaphragm wall structure according to claim 1, wherein in the first step, a distributed optical fiber monitoring network is constructed, comprising: the self-heating fiber Bragg grating temperature sensor and the main ribs are bound and laid on the top, the bottom or the inner surface and the outer surface of the surface layer of the reinforcement cage structure of the underground continuous wall, and are arranged in a grid mode.

3. The leakage monitoring method for an underground diaphragm wall structure according to claim 2, wherein the self-heating fiber bragg grating temperature sensor adopts a PID controller to carry out closed-loop control on self-heating temperature.

4. The leakage monitoring method for an underground diaphragm wall structure according to claim 1, wherein in the fourth step, the data analysis is performed on the sensed data of the distributed optical fiber monitoring network, and the method comprises the following steps:

performing numerical simulation processing on the sensing data by using auxiliary software and hardware;

completing wavelet analysis, quantitative analysis, data characterization processing and data network processing of the sensing data based on a database;

performing secondary analysis and raw data processing with the aid of leakage information, the leakage information comprising: assistance information, location information, spatial positioning and evaluation criteria.

5. The leakage monitoring method for an underground diaphragm wall structure according to claim 1, wherein in the fifth step, safety decision making is completed according to the analysis result of the infiltration information of the underground diaphragm wall structure, and the safety decision includes early warning processing decision, dangerous alarm processing decision, safety evaluation processing decision and disaster coping mode.

6. A leak monitoring system for use in an underground diaphragm wall structure, comprising:

the self-heating optical fiber Bragg grating temperature sensor, the data acquisition equipment and the remote host;

the self-heating fiber Bragg grating temperature sensor is utilized to lay a sensing optical cable circuit on the underground continuous wall structure, a distributed fiber monitoring network is constructed, and key leakage monitoring of the underground continuous wall structure is realized;

the data acquisition equipment comprises an optical fiber regulator and a field host, is connected with a self-heating optical fiber Bragg grating temperature sensor through an optical fiber line, demodulates and measures the self-heating optical fiber Bragg grating temperature sensor, acquires sensing data of a distributed optical fiber monitoring network and transmits the sensing data to a remote host;

and the remote host analyzes and processes the sensing data based on the auxiliary software and hardware, the database and the penetration information unit, and finally completes the security decision making.