Cast-in-situ bored pile whole life cycle monitoring method and system based on composite optical cable

Abstract

The invention relates to the technical field of cast-in-situ bored pile monitoring, in particular to a cast-in-situ bored pile full-life-cycle monitoring method and system based on a composite optical cable. The cast-in-situ bored pile full-life-cycle monitoring method based on the composite optical cable comprises the steps that after concrete pouring is completed and concrete hydration heat tends to be stable, a cast-in-situ bored pile is monitored; temperature data and initial central wavelengths measured by the temperature optical fiber sensors with different depths and initial central wavelengths measured by the strain optical fiber sensors with different depths are obtained, the pile body is heated, temperature data measured by the temperature optical fiber sensors with different depths after heating are obtained, and the temperature data of the strain optical fiber sensors with different depths are obtained according to the temperature data before and after heating. The mud content condition in the whole pile body range is calculated, and pile body defects are judged; and current central wavelengths measured by the temperature optical fiber sensors and the strain optical fiber sensors at different depths are obtained in real time, and pile body axial force distribution and side friction resistance are calculated. By means of the composite optical cable arranged in the cast-in-situ bored pile, the requirement for multi-parameter monitoring of the whole life cycle of the cast-in-situ bored pile is met.

Description

Technical Field

[0001] The present invention relates to the technical field of bored cast-in-place pile monitoring, and in particular to a method and system for monitoring the entire life cycle of bored cast-in-place piles based on composite optical cables. Background Art

[0002] Bored piles are one of the most commonly used foundation structures because of their high bearing capacity and simple construction process. The construction process is to drill holes on site, lower the steel cage, and finally pour concrete. It is an underground hidden project. If there are defects in the quality of the piles, it will seriously affect the upper structure. It is necessary to monitor the construction parameters of bored piles and the stress state during operation in real time to ensure the quality of the pile foundation. During the concrete pouring stage, it is necessary to control the buried depth of the conduit during the pouring process to avoid the conduit being pulled out of the concrete surface, causing quality risks such as broken piles and mud; during the pile inspection stage, it is necessary to evaluate the integrity of the pile body and take corresponding measures to deal with the defects of the pile body; during long-term operation, it is necessary to analyze the stress on the pile body, evaluate the health of the pile foundation, and take corresponding measures to repair the defective parts.

[0003] However, there are many types of monitoring parameters during the construction and operation of bored cast-in-place piles, and the monitoring methods are relatively scattered. For example, during the pouring of concrete, a manual hammer or pressure sensor is used to monitor the concrete liquid level; after the pile is completed, an ultrasonic hole-forming detection instrument is used to detect the integrity of the pile body; during operation, the pre-buried stress / strain monitoring elements are used to obtain the stress and strain of the pile body to analyze the bearing capacity of the pile foundation and evaluate the health of the pile foundation. Therefore, the workload of laying out monitoring elements during the construction and operation of bored cast-in-place piles is large, and the labor and equipment costs are high. It is urgent to develop a system and method that can achieve full life cycle monitoring by deploying sensors once, reducing the workload of sensor deployment and saving labor and equipment costs. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and to provide a full life cycle monitoring method and system for bored cast-in-place piles based on composite optical cables. By utilizing the composite optical cables arranged in the bored cast-in-place piles, the multi-parameter monitoring needs of the full life cycle of the bored cast-in-place piles are realized, namely, monitoring of the concrete pouring height during the concrete pouring process, monitoring of pile body defects after the concrete pouring is completed and the concrete hydration heat tends to be stable, and monitoring of the pile body axial force distribution and lateral friction resistance during the operation stage.

[0005] In order to solve the above technical problems, on the one hand, the present invention provides a method for monitoring the full life cycle of bored piles based on a composite optical cable, comprising:

[0006] After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data and initial center wavelength measured by the temperature optical fiber sensors at different depths, as well as the initial center wavelength measured by the strain optical fiber sensors at different depths are obtained, the pile body is heated, and the temperature data measured by the temperature optical fiber sensors at different depths after heating are obtained. Based on the temperature data before and after heating, the mud content in the entire pile body is calculated to determine the defects of the pile body;

[0007] The current central wavelength measured by the temperature optical fiber sensor and strain optical fiber sensor at different depths is obtained in real time to calculate the axial force distribution and lateral friction resistance of the pile body.

[0008] Furthermore, methods for determining pile body defects include:

[0009] After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data T measured by each temperature optical fiber sensor at different depths are obtained. 01 , T 02 ,……,T 0n , T 0n It is the temperature data measured by the nth temperature optical fiber sensor before heating;

[0010] The pile body is heated. After the pile body and the temperature optical fiber sensor are in a stable temperature field, the temperature data T measured by each temperature optical fiber sensor at different depths after heating are obtained. 11 , T 12 ,……,T 1n , T 1n is the temperature data measured by the nth temperature optical fiber sensor after heating;

[0011] The mud content of the pile body at the corresponding depth of each temperature optical fiber sensor is calculated according to the temperature data before and after heating;

[0012] Determine the defects of the pile body based on the mud content in the pile body.

[0013] Furthermore, the calculation method of the pile body mud content includes:

[0014] According to ΔT=T 1i -T 0i =α i p+c, calculate the pile body temperature rise coefficient α i ,according to Calculate the mud content in the entire pile body, where ΔT is the temperature rise value, T 1i is the temperature data measured by the ith temperature optical fiber sensor after heating, T 0i is the temperature data measured by the i-th temperature optical fiber sensor before heating, α iis the temperature rise coefficient of the pile body at the corresponding depth of the ith temperature optical fiber sensor, p is the heating power, c is a constant, a0 and b0 are the calibration coefficients of the laboratory mud content and the temperature rise coefficient, and w i is the mud content of the pile body at the corresponding depth of the i-th temperature optical fiber sensor.

[0015] Furthermore, the method for calculating the axial force distribution and lateral friction of the pile body includes:

[0016] According to the central wavelength changes of the temperature optical fiber sensor and the strain optical fiber sensor, the strain distribution of the pile body after temperature compensation is calculated;

[0017] Based on the calculated strain distribution of the pile body, the axial force and lateral friction at different depths of the pile body are calculated.

[0018] Furthermore, the method for calculating the temperature-compensated pile strain distribution includes:

[0019] according to Calculate the strain at different depths of the pile body, where ε i is the pile strain at the corresponding depth of the i-th strain optical fiber sensor, λ Si is the initial central wavelength measured by the i-th strain optical fiber sensor, K i is the calibration coefficient of the i-th strain optical fiber sensor, Δλ Si is the change of the current central wavelength measured by the i-th strain optical fiber sensor relative to the initial central wavelength, Δλ Ti is the change of the current central wavelength measured by the i-th temperature optical fiber sensor relative to the initial central wavelength.

[0020] Furthermore, the method for calculating the axial force and lateral friction at different depths of the pile body includes:

[0021] According to Q(z i )=ε i EA calculates the axial force at different depths of the pile body, where Q(zi) is the axial force of the pile body at the corresponding depth of the i-th strain optical fiber sensor, z i =(ni)d, d is the distance between two adjacent strain optical fiber sensors, E is the elastic modulus of the pile body, and A is the cross-sectional area of ​​the pile body;

[0022] according to Calculate the side friction resistance of the pile at different depths, where q s (z i ) is the lateral friction resistance at the corresponding depth of the i-th strain optical fiber sensor, and U is the circumference of the pile body.

[0023] Further, including:

[0024] During the concrete pouring process, the temperature data measured by the temperature fiber optic sensors at different depths are obtained in real time, and the current concrete pouring height is calculated in real time.

[0025] Furthermore, the current calculation method of the concrete pouring height includes:

[0026] Determine the interval of the concrete interface according to the following formula:

[0027]

[0028] Among them, T i is the temperature data measured by the ith temperature optical fiber sensor during concrete pouring, T 混 is the temperature of concrete pouring, C is the set temperature difference, m <n;

[0029] It is determined that the concrete interface is located between the mth temperature optical fiber sensor and the m+1th temperature optical fiber sensor, and the current concrete pouring height H=d×m.

[0030] On the other hand, the present invention provides a full life cycle monitoring system for bored piles based on composite optical cables, including composite optical cables, fiber grating demodulators, and data processing modules;

[0031] The composite optical cable is installed on the steel cage of the bored pile, and the composite optical cable includes an arrayed temperature fiber grating, an arrayed strain fiber grating and a heating strip, the arrayed temperature fiber grating includes a plurality of temperature fiber sensors, the arrayed strain fiber grating includes a plurality of strain fiber sensors, the plurality of temperature fiber sensors and the plurality of strain fiber sensors are uniformly arranged along the depth direction of the bored pile, and each temperature fiber sensor corresponds to a strain fiber sensor with the same depth, and the heating strip is used to heat the pile body;

[0032] The fiber grating demodulator is connected to the composite optical cable, and the fiber grating demodulator uses the composite optical cable to measure temperature and central wavelength;

[0033] The data processing module is used to obtain the collected data of the fiber grating demodulator and calculate the mud content, pile body axial force distribution and lateral friction resistance within the entire pile body.

[0034] Furthermore, the composite cable includes an enclosure, which encloses the arrayed temperature fiber grating, the arrayed strain fiber grating and the heating strip. A steel pipe is arranged in the enclosure, and the arrayed temperature fiber grating is arranged in the steel pipe and kept in a relaxed state.

[0035] The beneficial effects of the present invention are:

[0036] 1. The present invention utilizes a composite optical cable arranged in a bored cast-in-place pile to achieve the multi-parameter monitoring requirements of the bored cast-in-place pile throughout its life cycle, namely, monitoring of the concrete pouring height during the concrete pouring process, monitoring of pile body defects after the concrete pouring is completed and the concrete hydration heat tends to be stable, and monitoring of the pile body axial force distribution and lateral friction resistance during the operation stage, thereby reducing the workload of sensor layout and saving labor and equipment costs.

[0037] 2. The present invention uses a temperature optical fiber sensor to monitor the temperature change before and after the pile body is heated, calculates the temperature rise coefficient based on the temperature change and the heating power, and then calculates the mud content in the entire pile body through the relationship between the temperature rise coefficient and the mud content, thereby determining the location of the pile body defects.

[0038] 3. When calculating the pile body strain, the present invention uses the central wavelength change measured by the strain optical fiber sensor to subtract the central wavelength change measured by the temperature optical fiber sensor, and performs temperature compensation on the entire pile body, thereby avoiding the influence of temperature changes on the pile body strain calculation, and the calculation results of the axial force and lateral friction resistance are more accurate.

[0039] 4. The present invention arranges the array-type temperature fiber Bragg grating in the steel pipe and keeps it in a relaxed state, thereby eliminating the influence of external stress on the array-type temperature fiber Bragg grating, making the array-type temperature fiber Bragg grating only sensitive to temperature and making the monitoring result more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the full life cycle monitoring system of bored piles based on composite optical cables of the present invention;

[0041] Figure 2 This is a schematic diagram of on-site installation of the composite optical cable of the present invention;

[0042] Figure 3 is a cross-sectional view of the composite optical cable of the present invention;

[0043] Figure 4 is a longitudinal cross-sectional view of the composite optical cable of the present invention;

[0044] Figure 5 The temperature monitoring curve during the concrete pouring process of the present invention;

[0045] Figure 6 This is the relationship curve between the stable temperature rise and the heating power of the present invention;

[0046] Figure 7 It is the relationship curve between the temperature rise coefficient and the mud content of the present invention;

[0047] Figure 8 It is the temperature monitoring diagram before and after heating of the present invention;

[0048] Fig. 9This is the strain calculation result curve of the present invention.

[0049] Reference numerals: composite optical cable 1; array temperature fiber Bragg grating 11; array strain fiber Bragg grating 12; heating strip 13; steel pipe 14; inclusion 15;

[0050] Fiber Bragg grating demodulator 2;

[0051] IoT gateway module 3;

[0052] Data processing module 4;

[0053] Heating power supply 5;

[0054] Optical fiber pay-off reel 6. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0056] like Figure 1 As shown, the present invention provides a full life cycle monitoring system for bored piles based on a composite optical cable, comprising a composite optical cable 1, a fiber grating demodulator 2, a data processing module 4, an Internet of Things gateway module 3, and a heating power supply 5;

[0057] The composite optical cable 1 is installed on the main reinforcement of the bored pile reinforcement cage, and is U-shaped as a whole. Figure 3 , 4 As shown, the composite optical cable 1 includes an arrayed temperature fiber grating 11, an arrayed strain fiber grating 12, a heating strip 13, and an inclusion 15; the arrayed temperature fiber grating 11, the arrayed strain fiber grating 12, and the heating strip 13 are all parallel to the composite optical cable 1.

[0058] The arrayed temperature fiber grating 11 includes n temperature fiber grating sensors, and the arrayed strain fiber grating 12 includes n strain fiber optic sensors. The n temperature fiber optic sensors and the n strain fiber optic sensors are evenly arranged along the depth direction of the bored piles. The distance between two adjacent temperature fiber optic sensors is d, and the distance between two adjacent strain fiber optic sensors is also d. Each temperature fiber optic sensor corresponds to a strain fiber optic sensor with the same depth. The bottom temperature fiber optic sensor is the first one, and the top temperature fiber optic sensor is the nth one.

[0059] The inclusion body 15 includes the arrayed temperature fiber grating 11, the arrayed strain fiber grating 12 and the heating strip 13. A steel pipe 14 is arranged in the inclusion body 15. The arrayed temperature fiber grating 11 is arranged in the steel pipe 14 and kept in a relaxed state. The inclusion body 15 can be made of fiber resin. Since the optical fiber is sensitive to both temperature and stress, keeping it in a relaxed state in the steel pipe 14 will eliminate the influence of stress, so that the arrayed temperature fiber grating 11 is only sensitive to temperature, and the monitoring result is more accurate.

[0060] The fiber grating demodulator 2 is connected to the composite optical cable 1, and the fiber grating demodulator 2 uses the composite optical cable 1 to measure the temperature and the central wavelength; the Internet of Things gateway module 3 is connected to the fiber grating demodulator 2 through a wired connection.

[0061] The heating strip 13 is used to heat the pile body. The heating strip 13 can adopt active heating carbon fiber filaments. The heating strip 13 is connected to the heating power supply 5.

[0062] The Internet of Things gateway module 3 is connected to the data processing module 4 via wireless. The data processing module 4 is used to obtain the collected data of the fiber grating demodulator 2 and calculate the mud content, pile body axial force distribution and lateral friction resistance within the entire pile body.

[0063] The full life cycle monitoring system for bored piles based on composite optical cables also includes a real-time monitoring module for concrete pouring elevation, a module for evaluating pile foundation integrity and defects, and a module for monitoring pile foundation stress and health status during operation. All modules compare the read data with parameter thresholds. If the read data exceeds the parameter threshold, the early warning management module will generate an alarm to alert relevant technical personnel and display the specific pile position number, possible abnormality type and location on the display end.

[0064] The installation steps of the composite optical cable-based bored pile life cycle monitoring system are as follows:

[0065] S1: Before the steel cage starts to be lowered, the optical fiber lowering reel 6 is placed at the hole;

[0066] S2: The steel cage is lowered, and during the lowering process, the composite optical cable 1 is fixedly connected to the steel cage by tying or gluing at intervals of 0.5 m;

[0067] S3: After the steel cage is lowered, a pre-tension is applied to the composite optical cable 1, and a certain length of the composite optical cable 1 is reserved at the position of the cast-in-place pile head;

[0068] S4: Connect the composite optical cable 1 to the fiber grating demodulator 2 through a jumper to detect the condition of the optical fiber line.

[0069] The monitoring method using the above-mentioned composite optical cable-based bored pile full life cycle monitoring system comprises:

[0070] During the concrete pouring process, the temperature data measured by the temperature optical fiber sensors at different depths are obtained in real time, and the current concrete pouring height is calculated in real time;

[0071] The current calculation methods for concrete pouring height include:

[0072] Determine the interval where the concrete interface is located according to the following formula:

[0073]

[0074] Among them, T i is the temperature data measured by the ith temperature optical fiber sensor during concrete pouring, T 混 is the temperature of concrete pouring, C is the set temperature difference, m <n;

[0075] It is determined that the concrete interface is located between the mth temperature optical fiber sensor and the m+1th temperature optical fiber sensor, and the current concrete pouring height H=d×m.

[0076] like Figure 5 As shown in FIG. 1 , a temperature curve during concrete pouring in a certain example, C=2°C, d=0.5m, and the concrete interface is located between the 35th temperature optical fiber sensor and the 36th temperature optical fiber sensor. Therefore, the current concrete pouring height H=0.5×35=17.5m. It can be understood that monitoring the concrete pouring height facilitates quality control during the construction process and the control of the concrete pouring volume, which can ensure quality and control costs.

[0077] After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data and initial center wavelength measured by the temperature optical fiber sensors at different depths, as well as the initial center wavelength measured by the strain optical fiber sensors at different depths are obtained, the pile body is heated, and the temperature data measured by the temperature optical fiber sensors at different depths after heating are obtained. Based on the temperature data before and after heating, the mud content in the entire pile body is calculated to determine the defects of the pile body;

[0078] Methods for judging pile body defects include:

[0079] After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data T measured by each temperature optical fiber sensor at different depths are obtained. 01 、T 02 ,……,T 0n , T 0n It is the temperature data measured by the nth temperature optical fiber sensor before heating;

[0080] The pile body is heated. After the pile body and the temperature optical fiber sensor are in a stable temperature field, the temperature data T measured by each temperature optical fiber sensor at different depths after heating are obtained. 11 、T12 ,……,T 1n , T 1n is the temperature data measured by the nth temperature optical fiber sensor after heating;

[0081] The mud content of the pile body at the corresponding depth of each temperature optical fiber sensor is calculated according to the temperature data before and after heating;

[0082] The calculation methods of pile mud content include:

[0083] According to ΔT=T 1i -T 0i =α i p+c, calculate the pile body temperature rise coefficient α i ,according to Calculate the mud content in the entire pile body, where ΔT is the temperature rise value, T 1i is the temperature data measured by the ith temperature optical fiber sensor after heating, T 0i is the temperature data measured by the i-th temperature optical fiber sensor before heating, α i is the temperature rise coefficient of the pile body at the corresponding depth of the ith temperature optical fiber sensor, p is the heating power, c is a constant, a0 and b0 are the calibration coefficients of the laboratory mud content and the temperature rise coefficient, and w i is the mud content of the pile body at the corresponding depth of the i-th temperature optical fiber sensor.

[0084] like Figure 8 As shown in FIG. 1 , in a certain example, after the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature curve is drawn by using the temperature data measured before and after the pile body is heated by the heating strip 13, and the heating time is 24 hours. Figure 7 As shown in the figure, in the laboratory, different mud contents are used to heat the samples with different heating powers, and the pile body temperature rise coefficient α corresponding to different mud contents can be obtained. The relationship curve between the mud content and the pile body temperature rise coefficient α can be drawn, fitted, and the values ​​of a0 and b0 can be obtained. Among them, the calculation method of the pile body temperature rise coefficient α corresponding to different mud contents is as follows: Figure 6 As shown in the figure, under a certain mud content, the stable temperature rise is measured by heating with different heating powers for the same time. The relationship curve between heating power and stable temperature rise is drawn and fitted to obtain the pile body temperature rise coefficient α. Figure 6 , α=0.39429.

[0085] for Figure 8 In the example shown, the temperature rise values ​​before and after heating and the heating power of the heating strip 13 can be used to obtain the pile body temperature rise coefficient at the corresponding depth of each temperature optical fiber sensor. The mud content at the corresponding depth of each temperature optical fiber sensor can be obtained. According to the calculation results, it can be seen that there are slag inclusion defects at two places on the pile body, which just correspond to the positions with smaller temperature rise values.

[0086] The current central wavelength measured by the temperature optical fiber sensor and strain optical fiber sensor at different depths is obtained in real time to calculate the axial force distribution and lateral friction resistance of the pile body.

[0087] Methods for calculating the axial force distribution and lateral friction of the pile body include:

[0088] According to the central wavelength changes of the temperature optical fiber sensor and the strain optical fiber sensor, the strain distribution of the pile body after temperature compensation is calculated;

[0089] The methods for calculating the temperature-compensated pile strain distribution include:

[0090] according to Calculate the strain at different depths of the pile body, where ε i is the pile strain at the corresponding depth of the i-th strain optical fiber sensor, λ Si is the initial central wavelength measured by the i-th strain optical fiber sensor, K i is the calibration coefficient of the i-th strain optical fiber sensor, Δλ Si is the change of the current central wavelength measured by the i-th strain optical fiber sensor relative to the initial central wavelength, Δλ Ti is the change of the current center wavelength measured by the i-th temperature optical fiber sensor relative to the initial center wavelength. Si -Δλ Ti , eliminating the influence of temperature on the strain calculation results, making the calculation results more accurate.

[0091] Based on the calculated strain distribution of the pile body, the axial force and lateral friction at different depths of the pile body are calculated.

[0092] Methods for calculating the axial force and lateral friction at different depths of the pile include:

[0093] According to Q(z i )=ε i EA calculates the axial force at different depths of the pile body, where Q(zi) is the axial force of the pile body at the corresponding depth of the i-th strain optical fiber sensor, z i =(ni)d, d is the distance between two adjacent strain optical fiber sensors, E is the elastic modulus of the pile body, and A is the cross-sectional area of ​​the pile body;

[0094] according to Calculate the side friction resistance of the pile at different depths, where q s (z i ) is the lateral friction resistance at the corresponding depth of the i-th strain optical fiber sensor, and U is the circumference of the pile body.

[0095] like Fig. 9The figure shows a curve of strain calculation results in an example. It can be found that there is a sharp increase in strain at a depth of 15m to 17.5m, indicating that the pile body has been damaged. To determine whether the pile body has been damaged, if ε i >1.2maxε i-1 ,ε i+1 , it can be determined that the pile body at the depth corresponding to the i-th strain optical fiber sensor is damaged.

[0096] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for monitoring the entire life cycle of bored piles based on composite optical cables, characterized in that: include: After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data and initial center wavelength measured by the temperature optical fiber sensors at different depths, as well as the initial center wavelength measured by the strain optical fiber sensors at different depths are obtained, the pile body is heated, and the temperature data measured by the temperature optical fiber sensors at different depths after heating are obtained. Based on the temperature data before and after heating, the mud content in the entire pile body is calculated to determine the defects of the pile body; The current central wavelength measured by the temperature optical fiber sensor and strain optical fiber sensor at different depths is obtained in real time to calculate the axial force distribution and lateral friction resistance of the pile body.

2. The method for monitoring the full life cycle of bored piles based on composite optical cables according to claim 1 is characterized in that: Methods for judging pile body defects include: After the concrete pouring is completed and the concrete hydration heat tends to be stable, the temperature data T measured by each temperature optical fiber sensor at different depths are obtained. 01 , T 02 ,……,T 0n , T 0n It is the temperature data measured by the nth temperature optical fiber sensor before heating; The pile body is heated. After the pile body and the temperature optical fiber sensor are in a stable temperature field, the temperature data T measured by each temperature optical fiber sensor at different depths after heating are obtained. 11 , T 12 ,……,T 1n , T 1n is the temperature data measured by the nth temperature optical fiber sensor after heating; The mud content of the pile body at the corresponding depth of each temperature optical fiber sensor is calculated according to the temperature data before and after heating; Determine the defects of the pile body based on the mud content in the pile body.

3. The method for monitoring the full life cycle of bored piles based on composite optical cables according to claim 2 is characterized in that: The calculation methods of pile mud content include: According to ΔT=T 1i -T 0i =α i p+c, calculate the pile body temperature rise coefficient α i ,according to Calculate the mud content in the entire pile body, where ΔT is the temperature rise value, T 1i is the temperature data measured by the ith temperature optical fiber sensor after heating, T 0i is the temperature data measured by the i-th temperature optical fiber sensor before heating, α i is the temperature rise coefficient of the pile body at the corresponding depth of the ith temperature optical fiber sensor, p is the heating power, c is a constant, a0 and b0 are the calibration coefficients of the laboratory mud content and the temperature rise coefficient, and w i is the mud content of the pile body at the corresponding depth of the i-th temperature optical fiber sensor.

4. The method for monitoring the full life cycle of bored piles based on composite optical cables according to any one of claims 1 to 3, characterized in that: Methods for calculating the axial force distribution and lateral friction of the pile body include: According to the central wavelength changes of the temperature optical fiber sensor and the strain optical fiber sensor, the strain distribution of the pile body after temperature compensation is calculated; Based on the calculated strain distribution of the pile body, the axial force and lateral friction at different depths of the pile body are calculated.

5. The method for monitoring the entire life cycle of bored piles based on composite optical cables according to claim 4 is characterized in that: The methods for calculating the temperature-compensated pile strain distribution include: according to Calculate the strain at different depths of the pile body, where ε i is the pile strain at the corresponding depth of the i-th strain optical fiber sensor, λ Si is the initial central wavelength measured by the i-th strain optical fiber sensor, K i is the calibration coefficient of the i-th strain optical fiber sensor, Δλ Si is the change of the current central wavelength measured by the i-th strain optical fiber sensor relative to the initial central wavelength, Δλ Ti is the change of the current central wavelength measured by the i-th temperature optical fiber sensor relative to the initial central wavelength.

6. The method for monitoring the entire life cycle of bored piles based on composite optical cables according to claim 5 is characterized in that: Methods for calculating the axial force and lateral friction at different depths of the pile include: According to Q(z i )=ε i EA calculates the axial force at different depths of the pile body, where Q(zi) is the axial force of the pile body at the corresponding depth of the i-th strain optical fiber sensor, z i =(ni)d, d is the distance between two adjacent strain optical fiber sensors, E is the elastic modulus of the pile body, and A is the cross-sectional area of ​​the pile body; according to Calculate the side friction resistance of the pile at different depths, where q s (z i ) is the lateral friction resistance at the corresponding depth of the i-th strain optical fiber sensor, and U is the circumference of the pile body.

7. The method for monitoring the full life cycle of bored piles based on composite optical cables according to any one of claims 1 to 3, characterized in that: include: During the concrete pouring process, the temperature data measured by the temperature fiber optic sensors at different depths are obtained in real time, and the current concrete pouring height is calculated in real time.

8. The method for monitoring the full life cycle of bored piles based on composite optical cables according to claim 7 is characterized in that: The current calculation methods for concrete pouring height include: Determine the interval of the concrete interface according to the following formula: Among them, T i is the temperature data measured by the ith temperature optical fiber sensor during concrete pouring, T 混 is the temperature of concrete pouring, C is the set temperature difference, m <n; It is determined that the concrete interface is located between the mth temperature optical fiber sensor and the m+1th temperature optical fiber sensor, and the current concrete pouring height H=d×m.

9. A full life cycle monitoring system for bored piles based on composite optical cables, characterized by: It comprises a composite optical cable (1), a fiber grating demodulator (2), and a data processing module (4); The composite optical cable (1) is installed on a steel cage of a bored pile. The composite optical cable (1) comprises an arrayed temperature optical fiber grating (11), an arrayed strain optical fiber grating (12) and a heating strip (13). The arrayed temperature optical fiber grating (11) comprises a plurality of temperature optical fiber sensors. The arrayed strain optical fiber grating (12) comprises a plurality of strain optical fiber sensors. The plurality of temperature optical fiber sensors and the plurality of strain optical fiber sensors are uniformly arranged along the depth direction of the bored pile, and each temperature optical fiber sensor corresponds to a strain optical fiber sensor at the same depth. The heating strip (13) is used for heating the pile body. The fiber grating demodulator (2) is connected to the composite optical cable (1), and the fiber grating demodulator (2) uses the composite optical cable (1) to measure temperature and central wavelength; The data processing module (4) is used to obtain the collected data of the fiber optic Bragg grating demodulator (2) and calculate the mud content, pile body axial force distribution and lateral friction resistance within the entire pile body.

10. The full life cycle monitoring system for bored piles based on composite optical cables according to claim 9 is characterized in that: The composite cable comprises an enclosure (15), wherein the enclosure (15) encloses an arrayed temperature fiber grating (11), an arrayed strain fiber grating (12) and a heating strip (13); a steel pipe (14) is arranged in the enclosure (15), and the arrayed temperature fiber grating (11) is arranged in the steel pipe (14) and maintained in a relaxed state.

Images