CN108168923B - Method for measuring dam collapse risk of concrete gravity danger dam - Google Patents
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Abstract
The invention relates to a method for measuring the dam collapse risk of a concrete gravity dangerous dam, and belongs to the field of hydraulic engineering. The method comprises the steps of firstly, detecting the concrete gravity type dangerous dam by using an acoustic wave chromatography detection technology, namely, comprehensively detecting the gravity type dangerous dam by using the acoustic wave chromatography technology to determine the worst dangerous section of a dam body, then, providing and establishing dynamic elastic modulus parameters for dynamic measurement and stability evaluation of the risk of dam collapse of the concrete gravity type dangerous dam on the basis of the detection, monitoring the most unfavorable dangerous section change rule of the gravity type dangerous dam under the condition of reservoir water level change by using the parameters, and comprehensively evaluating and analyzing the dynamic elastic modulus change rule of the dangerous section by using the unit dynamic damage rate and the unit time damage rate, thereby achieving the evaluation and prediction of the dynamic stability, the durability and the like of the concrete gravity type dangerous dam.
Description
Technical Field
The invention relates to a method for measuring the dam collapse risk of a concrete gravity dangerous dam, and belongs to the field of hydraulic engineering.
Background
With the rapid development of the building industry in China, the urbanization construction is accelerated continuously, and concrete becomes one of the most important structural materials in the civil engineering fields of national infrastructure, traffic, water conservancy and the like. In China, the consumption of concrete is hundreds of millions of cubic meters, and the concrete is widely applied to roads, house construction, bridges and national defense construction. However, concrete is usually applied in a complex environment, and in the process of concrete service, factors such as chemical erosion, external load and natural conditions (temperature cycling and freezing) often cause cumulative damage and destruction of the concrete engineering, and in a severe case, even catastrophic accidents can occur. Therefore, it is very important to adopt necessary monitoring means to implement real-time dynamic monitoring and early warning on large concrete engineering (concrete gravity dam, concrete bridge) structures and ensure safe operation during the service period.
Concrete gravity dams age due to the special working environment of the concrete gravity dams, under the action of natural conditions (cyclic temperature change, freezing and the like) and repeated changes of hydrodynamic force. Therefore, it is necessary to know the internal property change of the dam body and the occurrence of the internal dangerous fracture after the dam works for a long time. The traditional mode is that instruments such as a stress meter, a strain gauge, a side seam meter and the like are buried in the cross section of a dam body, the working state of the dam is known according to the monitoring result of the instruments, but the position of the dam where the dam is aged and damaged in the long-term operation process is not necessarily on the cross section of the originally buried instrument, and in addition, the instruments buried in the dam are gradually ineffective after the dam operates for decades and cannot be monitored any more. Therefore, the traditional method can not meet the urgent requirements of people on the safe use and monitoring of the dam.
In order to guarantee the safety of the concrete gravity dam, it is very important to detect and evaluate various performance indexes of the concrete gravity dam, the damage of the concrete is a long-term accumulated process, and the concrete gravity dam needs to be monitored on line for a long time if necessary so as to ensure the safety of the concrete gravity dam in a service period. At present, the existing detection means for the concrete dam can be divided into a damaged detection technology and a nondestructive detection technology: the method is characterized in that the method is capable of obtaining actual damage resistance to local damage of the concrete member, and is visual and reliable, and the result obtained by testing is easy to be received by people; the method has the defects that the local part of the concrete member is damaged, secondary repair is needed after detection, and the method is not suitable for detection of large-area concrete members, so that the gravity type dangerous dam can be damaged to a certain extent by the method, and the method is not adopted generally. With the rapid development of scientific technology, the nondestructive testing technology gradually breaks through the original scope, and a batch of new testing methods are emerging, including microwave absorption, radar scanning, infrared imaging, pulse echo, laser application, Nuclear Magnetic Resonance (NMR) method, acoustic emission detection method and the like. The nondestructive testing method is generally applied to structural concrete quality testing, and obtains better technical and economic effects.
Disclosure of Invention
The invention provides a method for measuring the risk of breaking a concrete gravity type dangerous dam by comprehensively detecting the concrete gravity type dangerous dam by using an acoustic chromatography detection technology, aiming at the defects and limitations of the conventional method for measuring the concrete gravity dam.
The technical scheme for solving the technical problems is as follows:
a method for measuring the dam collapse risk of a concrete gravity danger dam comprises the following steps:
step one, determining main measurement parameters of dam
According to the characteristics and requirements of the dam for monitoring the sound waves, 10 cubes with the side lengths of 150mm at different parts of the upper part, the middle part and the bottom of the dam body are selected, and a formula is utilized
Measuring the density ρ of each test pieceiTaking the arithmetic mean value of the density and the density as the density rho of the dam body;
step two, determining the detection position and the dangerous section of the gravity type dangerous dam monitoring instrument
The ST-2000 type acoustic tomography detection system is arranged from one end of a dam along the longitudinal direction, mainly comprises a high-frequency electric spark vibration source and a speed type detector, and is arranged in a mode shown in figure 1:
1) determining the rise amplitude delta H of the reservoir water level every year according to reservoir water scheduling information of a local reservoir area, and selecting the lowest water level H0 corresponding to the dry season every year to carry out initial measurement on the dam body. The method comprises the steps of arranging detection points at the position of the DE surface above the water surface of a dam body by manually using a rope, uniformly arranging 10 ST-2000 type detectors along the DE surface, uniformly arranging monitoring points along the AB surface by using a high-frequency electric spark vibration source, and descending the vibration source to the next monitoring point along the monitoring points once the vibration source sounds until the vibration source reaches the water surface.
2) The vibration source gradually emits sound waves, and the emitted sound waves are received and detected on the surface of the dam body DE. In the detection process, the detector can receive a signal once every time the vibration source transmits, in order to ensure the accuracy of received waveforms, the vibration source should transmit signals for a plurality of times, the transmission times are 5 times by combining practical engineering experience and considering the operability of an ST-2000 system.
3) And then moving a certain distance delta L along the longitudinal direction of the dam (L is the longitudinal length of the dam body) to arrange a detection system, and repeating the process until the detection system moves to the other end part of the dam.
4) In the process, the position of the dangerous section of the gravity type dangerous dam is determined according to the abnormal condition of the waveform received by the detector, and the judgment mode is as follows: when the envelope curve of the received waveform is semicircular, judging that the section of the position where the speed type detector is located is normal; when the envelope curve of the waveform is in a horn shape, the section where the velocity detector is located is judged to be abnormal, and accordingly the position of the dangerous section of the gravity type dangerous dam is determined (see the principle 1 for details).
Determining initial dynamic elastic modulus, hydrodynamic dynamic elastic modulus and creep dynamic elastic modulus of gravity type dangerous dam
The gravity type dangerous dam dangerous section has dynamic Poisson ratio v and dynamic elastic modulus E under the condition of reservoir water level or time changedWith the velocity V of the longitudinal wavePAnd the wave velocity V of the transverse waveSThe relation of the formulas (1) and (2) exists between the two,
wherein E isdDynamic elastic modulus of gravity type danger dam, V-dynamic Poisson's ratio of dam body, VPVelocity of longitudinal wave, VS-transverse wave velocity, ρ -dam body density;
therefore, only the longitudinal wave velocity V of each stage is obtainedPWith the velocity V of the transverse waveSUnder the condition, the gravity type dangerous dam initial dynamic elastic modulus E can be respectively determined according to the formulas (1) and (2)d0And the dangerous section arbitrarily rises hiHydrodynamic dynamic elastic die EdiAnd any tiCreep dynamic elastic modulus E at momentdti；
1) Gravity type danger dam initial dynamic elastic modulus Ed0Is determined
When the dam is at a low water level, because a plurality of detectors are arranged on the DE surface of the dam body, after the vibration source sends out signals, each detector receives a received waveform, namelyMultiple longitudinal and transverse wave velocities VP、VSThe wave velocity value is obtained by taking the longitudinal wave velocity V and the transverse wave velocity V of each detector when calculating the value of the initial dynamic elastic modulus in order to ensure the accuracy of the detection resultP、VSAs a result of the calculation. Therefore, when the dam is at low water level, the whole dam is in the elastic deformation stage, and the longitudinal wave speed V and the transverse wave speed V of each normal section are takenP、VSIs given as VP0、VS0Substituting the formula (1) and the formula (2) to obtain the gravity type dangerous dam initial dynamic elastic modulus Ed0。
2) Gravity type dangerous dam dangerous section hydrodynamic dynamic elastic die EdiIs determined
With the increase of reservoir water level, the gravity type dangerous dam bears the water pressure from reservoir water at the moment and shows a growing trend, and the dynamic elastic modulus of the dangerous section can be changed under the action of the change of the water pressure on the dangerous section of the dam. The method is used for monitoring the dam once every time the reservoir water level is drawn up by delta H/10, and the monitoring method is the same as the second step. Recording the value of the movable elastic die after the reservoir water level rises hi as the movable elastic die E when the reservoir water level risesdiAfter the water level rises, the average value V of the wave velocity of the longitudinal wave and the wave velocity of the transverse wave received by each detector of the dangerous sectionPi、VSiSubstituting into formulas (1) and (2) to obtain hydrodynamic dynamic elastic modulus E of any hi water level of dangerous sectiondi；
3) Gravity type dangerous dam dangerous section creep dynamic elastic die EdtiIs determined
When the water level of the dangerous section of the gravity type dangerous dam is not changed, the change of a dynamic elastic mode of the dangerous section is influenced by time change, so that the average value V of the longitudinal wave speed and the transverse wave speed of the dangerous section at the initial t0 static water level is recorded by the detector under the condition that the water level of the reservoir is static and unchanged when the water level of the reservoir reaches the peak valuept0、VSt0And the average value V of the wave speeds of the longitudinal wave and the transverse wave received by each detector of the dangerous section at the moment tiPti、VStiCalculating the dynamic elastic modulus E of the dangerous section creep at the initial static time t0 and the time ti after the water level reaches the peak value by the formulas (1) and (2) respectivelydt0And Edti。
Step four, determining hydrodynamic damage change rate of gravity type dangerous dam dangerous section changing along with reservoir water level
Raising reservoir water level hiHigh dangerous section hydrodynamic dynamic elastic die EdiVariation and dam initial dynamic elastic modulus Ed0The ratio of the two is recorded as the damage variable xi of the dangerous section of the gravity type dangerous damiValue xi of damage variable measured before water level rises0As an initial damage variable, the amount of damage,
and the value xi of the initial damage variable0Corresponding xiiThe ratio of the difference to the water level amplitude Δ H is defined as the hydrodynamic damage change rate
Step five, determining the creep damage change rate of the dangerous section of the gravity type dangerous dam along with the change of time
Will tiMoment dangerous section dynamic elastic die Edti' variation relative to initial dynamic elastic modulus and initial dynamic elastic modulus Ed0The ratio is denoted as tiDamage variable xi at timetiThe value of which is determined according to equation (5), t0The damage variable value measured at the moment is the static initial damage variable xi of the water levelt0：
And correspond to tiDamage variable xi at timetiInitial damage variable xi relative to water level statict0The ratio of the difference to the time Deltat, defined as the creep damage change rate, is determined according to equation (6),
step six, judging the magnitude of the gravity danger dam bursting risk by utilizing the hydrodynamic force type damage change rate and the creep deformation type damage change rate
Through the change characteristics of unit power damage rate and unit time damage rate of above analysis gravity type danger dam dangerous section, this patent combines both to combine the analysis gravity type danger dam risk of bursting together and has the accuracy of comprehensiveness, early warning, can draw following criterion according to the change of both values:
when the slope of the curve of the hydrodynamic damage change rate lambada i is positive and the slope of the curve of the creep damage change rate lambada ti is positive, the dam break risk caused by the dangerous section of the gravity dam is judged to be large, a red early warning is issued, and necessary treatment is carried out on the gravity dangerous dam in a reinforcing, flood discharging and other modes in time.
When the slope of the curve of the hydrodynamic force type damage change rate lambada i is positive and the slope of the curve of the creep type damage change rate lambada ti is negative, yellow early warning is issued at the moment, and the monitoring frequency is enhanced.
When the slope of the curve of the hydrodynamic force type damage change rate lambada i is negative and the slope of the curve of the creep type damage change rate lambada ti is negative, the safety of the gravity type dangerous dam dangerous section structure is determined to be within the use requirement range under the combined action of reservoir water level and time change.
Basic principle
Principle 1:
the waveform is the waveform of the received wave displayed on the upper surface of the detector, the internal structure of the detector is intact concrete, and the ultrasonic wave received waveform is an attenuated sine wave, and the envelope curve of the ultrasonic wave is approximately semicircular (as shown in figure 2-1). When the ultrasonic wave propagates in the concrete with problems, the propagation path of the ultrasonic wave changes due to internal defects, pitted surfaces, honeycombs or cracks of the concrete, and finally the waveform changes, and the envelope curve of the waveform is approximately trumpet-shaped (as shown in fig. 2-2). Therefore, the dangerous section of the gravity dam can be judged through the change of the waveform detected by the detection instrument.
Principle 2:
longitudinal wave velocity V detected by detecting instrumentPVelocity V of sum transverse waveSAccording to the wave theory and the gravity of concreteThe density ρ and Poisson's ratio ν of the dam have the following relationship:
wherein:
e, elastic modulus of the gravity type dangerous dam;
v is the Poisson ratio of the dam body;
rho is the density of the dam body;
g is the shear elastic modulus of the dam body.
Poisson ratios V and V can be found out through two formulas 8 and 9PAnd VSThe relation between the two is obtained by the same principle to obtain the dynamic elastic modulus EdiAnd VPThe relationship (2) of (c). Respectively determining dynamic Poisson ratio v and dynamic elastic modulus E of gravity type dangerous dam dangerous section under the condition of reservoir water level change (or time change) by formulas (9) and (2)d。
Wherein:
Eda dynamic elastic mold of the gravity type dangerous dam dangerous section;
v is the dynamic Poisson ratio of the dam body;
VP-longitudinal wave velocity;
VS-the velocity of the shear wave;
rho is the dam body density.
The invention has the beneficial effects that: for the monitoring of the gravity type dangerous dam, the change condition of the internal structure of the gravity type dangerous dam needs to be known at any time, and the gravity type dangerous dam is dynamically monitored in real time. In order to overcome the defects and limitations of the traditional method, the dynamic elastic modulus parameter is selected as a dynamic monitoring parameter, namely, the dynamic elastic modulus Edi of the gravity type dangerous dam changing along with time under the condition of reservoir water level change is calculated by using an acoustic chromatography detection technology, the dynamic elastic modulus parameter is used as an evaluation parameter of the stability of the dangerous section of the gravity type dangerous dam changing along with time under the condition of reservoir water level change, the unit dynamic damage rate and the unit time damage rate are used for comprehensively detecting and evaluating the durability and the strength of the gravity type dangerous dam, and then the risk of the gravity type dangerous dam bursting is reasonably monitored and early warned.
Drawings
FIG. 1 is a schematic view of a position arrangement of an ST-2000 acoustic tomography system;
FIG. 2-1 is a schematic view showing the envelope curve of normal concrete in a semicircular shape;
FIG. 2-2 is a schematic view showing the flawed concrete envelope flare;
FIG. 3 is a hydrodynamic damage rate-reservoir water level change image;
FIG. 4 is a graph of creep damage rate of change versus time;
FIG. 5 is a flow chart of the present invention.
Detailed Description
The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
In order to better illustrate the invention, the gravity type dangerous dam collapse risk monitoring is carried out by taking a certain gravity type dam in Jiang oil City of Sichuan province as an example to prove the practical significance and value of the gravity type dangerous dam collapse risk monitoring. The dam is a concrete gravity type dam, the maximum dam height is 120.14m, the dam crest elevation is 660.14m, the dam crest length is 72m, the total reservoir capacity of the reservoir is 5.72 multiplied by 108m3, and 5.12 Wenchuan grade 8.0 earthquake causes different degrees of damage to the dam body, and as many as 90 cracks appear.
The basic steps are as follows:
the method comprises the following steps: determination of main measurement parameters of dam
Ten concrete test blocks with the side lengths of the upper part, the middle part and the bottom part of the dam being 150mm are selected, and the density rho of the dam is measured to be 2430kg/m3 according to the method of the geotechnical experiment.
Step two: arranging monitoring instruments to determine dangerous section of dam
1) Arranging a monitoring instrument: uniformly arranging high-frequency electric spark vibration source monitoring points from the dam crest to the position above the water surface; meanwhile, 10 ST-2000 detectors are arranged on the surface DE of the dam by manually using a rope, high-frequency electric spark vibration source monitoring points are uniformly arranged on the surface AB of the dam, the vibration source drops to the next monitoring point once until the vibration source reaches the part above the water surface, and the reservoir water level elevation of the dam body is 646.3m at the moment.
2) Determining the dangerous section of the dam body: the ST-2000 type acoustic wave chromatography detection system is arranged according to the steps, the part above the reservoir water level of the dam body is detected by moving the dam body every 7.2m (taking) longitudinally, the waveform received by the detector is monitored to determine the longitudinal dangerous section of the dam body (see principle 1), and meanwhile, the longitudinal wave velocity V passing through the non-dangerous section is recordedPWith the velocity V of the transverse waveSThe value is obtained.
Step three: determination of initial dynamic elastic modulus, hydrodynamic dynamic elastic modulus and creep dynamic elastic modulus of gravity type dangerous dam
1) Gravity type danger dam initial dynamic elastic modulus Ed0Determination of (1): respectively taking the longitudinal wave velocity V recorded by the step two and passing through each non-dangerous sectionPWith the velocity V of the transverse waveSIs given as VS0Then calculating the gravity type dangerous dam initial dynamic elastic modulus E according to the formulas (1) and (2)d0The values, calculated results are shown in table 1.
TABLE 1
2) Gravity typeDangerous dam dangerous section hydrodynamic dynamic elastic die EdiDetermination of (1): when a rainy season comes, the reservoir water level of the dam rises, and the dangerous section is influenced. At this time, the ST-2000 type detection system is fixed to the dangerous section, and the average value V of the wave velocities of the longitudinal wave and the transverse wave received by each detector of the section corresponding to the rise hi of the reservoir water level is measuredPi、VSiThen, calculating a gravity type dangerous dam dangerous section hydrodynamic dynamic elastic modulus E by the formulas (1) and (2)diThe calculation results are shown in Table 2.
TABLE 2
3) Gravity type creeping type dynamic elastic die E for dangerous section of dangerous damdtiDetermination of (1): when the reservoir water level reaches the peak value and is static and unchanged, the average value V of the wave velocity of longitudinal waves and transverse waves passing through the dangerous section at the initial static water level t0 is recorded by the detectorPt0、VSt0And the average value V of the wave speeds of the longitudinal wave and the transverse wave received by each detector of the dangerous section at the moment tiPti、VStiRespectively calculating static initial t0 after the water level reaches the peak value and dangerous section creep deformation type dynamic elastic modulus E at ti moment by formulas (1) and (2)dt0And EdtiThe calculation results are shown in Table 3.
TABLE 3
Step four, determining the hydrodynamic damage change rate of the dangerous section of the gravity type dangerous dam
Force type dynamic elastic mold E for dangerous dam dangerous section hydrodynamic force calculation through three stepsdiDangerous section hydrodynamic dynamic type dynamic elastic mould E for raising reservoir water level to hidiThe variation and the initial dynamic elastic modulus E of the damd0The ratio of the two is recorded as the damage variable xi of the dangerous section of the gravity type dangerous damiThe value is represented by formula (3)
The results of the determination and calculation are shown in Table 4:
and the value of the initial damage variable (xi)0) Corresponding xiiThe ratio of the difference to the water head difference Δ H is defined as the hydrodynamic damage change rate, and Δ H is 0.2m, and the calculation results are shown in table 4:
TABLE 4
Step five, determining creep damage change rate of dangerous section of gravity type dangerous dam
Calculating the corresponding dynamic elastic modulus value at the ti moment under the condition that the reservoir water level reaches the peak value through the third step, and calculating the dynamic elastic modulus E of the dangerous section at the ti momentdtiVariable quantity relative to initial dynamic elastic modulus and initial dynamic elastic modulus Ed0The ratio of the two is expressed as the damage variable xi at time titiThe value of the damage variable is determined according to the formula (5), and the damage variable value measured at the time t0 is the static initial damage variable xi of the water levelt0The calculation results are shown in Table 5:
and the damage variable xi corresponding to the time titiInitial damage variable xi relative to water level statict0The ratio of the difference to time Δ t was defined as the creep damage change rate, and the value was determined according to equation (6), where Δ t is 2d, and the calculation results are shown in table 5:
TABLE 5
Step six: judgment of gravity danger dam bursting risk
And (3) drawing hydrodynamic damage change rate-reservoir water level and creep damage change rate-time images, as shown in (3) and (4). From the figure we can see when the hydrodynamic damage change rate lambdaiThe slope of the curve is positive, and the creep damage change rate lambdatiThe slope of the curve is positive, and the dam break risk caused by the dangerous section of the gravity dam is proved to be large at the moment, a red early warning is issued, and effective measures are taken to process the dam.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (7)
1. A method for measuring the dam collapse risk of a concrete gravity danger dam is characterized by comprising the following steps:
step one, determining main measurement parameters of dam
According to the characteristics and requirements of the dam for monitoring the sound waves, 10 cubes with the side lengths of 150mm at different parts of the upper part, the middle part and the bottom of the dam body are selected, and a formula is utilized
Measuring the density ρ of each test pieceiTaking the arithmetic mean value of the density and the density as the density rho of the dam body;
step two, determining the detection position and the dangerous section of the gravity type dangerous dam monitoring instrument
Determining the rise delta H of the reservoir water level every year according to the reservoir water scheduling information of the local reservoir area, and selecting the minimum water level H corresponding to the dry season every year0Carrying out initial measurement on a dam body; ST-2000 type acoustic wave tomographic detection system capable of transmitting and receiving detection acoustic waves arranged in a longitudinal direction from one end of a dam, based on received waveformsDetermining the position of a dangerous section of the gravity type dangerous dam under the abnormal condition;
determining initial dynamic elastic modulus, hydrodynamic dynamic elastic modulus and creep dynamic elastic modulus of gravity type dangerous dam
The gravity type dangerous dam dangerous section has dynamic Poisson ratio v and dynamic elastic modulus E under the condition of reservoir water level or time changedWith the velocity V of the longitudinal wavePAnd the wave velocity V of the transverse waveSThe relation of the formulas (1) and (2) exists between the two,
wherein E isdDynamic elastic modulus of gravity type danger dam, V-dynamic Poisson's ratio of dam body, VPVelocity of longitudinal wave, VS-transverse wave velocity, ρ -dam body density;
at each stage of obtaining longitudinal wave velocity VPWith the velocity V of the transverse waveSUnder the condition, the gravity type dangerous dam initial dynamic elastic modulus E can be respectively determined according to the formulas (1) and (2)d0And the dangerous section arbitrarily rises hiHydrodynamic dynamic elastic die EdiAnd any tiCreep dynamic elastic modulus E at momentdti；
Step four, determining the hydrodynamic damage change rate of the dangerous section of the gravity type dangerous dam along with the change of the reservoir water level to raise the reservoir water level by hiHigh dangerous section hydrodynamic dynamic elastic die EdiVariation and dam initial dynamic elastic modulus Ed0The ratio of the two is recorded as the damage variable xi of the dangerous section of the gravity type dangerous damiValue xi of damage variable measured before water level rises0As an initial damage variable, the amount of damage,
change the initial damage intoMagnitude xi0Corresponding xiiThe ratio of the difference to the water level amplitude Δ H is defined as the hydrodynamic damage change rate
Step five, determining the creep damage change rate of the dangerous section of the gravity type dangerous dam along with the change of time
Will tiMoment dangerous section dynamic elastic die Edti' variation relative to initial dynamic elastic modulus and initial dynamic elastic modulus Ed0The ratio is denoted as tiDamage variable xi at timetiThe value of which is determined according to equation (5), t0The damage variable value measured at the moment is the static initial damage variable xi of the water levelt0：
Correspond to tiDamage variable xi at timetiInitial damage variable xi relative to water level statict0The ratio of the difference to the time Deltat, defined as the creep damage change rate, is determined according to equation (6),
step six, judging the magnitude of the gravity danger dam bursting risk by utilizing the hydrodynamic force type damage change rate and the creep deformation type damage change rate
According to the numerical value change of the hydrodynamic damage change rate and the creep damage change rate of the gravity type dangerous dam dangerous section, the following criterion is obtained:
when hydrodynamic type damage change rate lambdaiThe slope of the curve is positive, and the creep damage change rate lambdatiThe slope of the curve is positive, the dam break risk caused by judging the dangerous section of the gravity dam is larger, a red early warning is issued, and the gravity is timely reinforced, discharged and the likeCarrying out necessary treatment on the dangerous dam;
when hydrodynamic type damage change rate lambdaiThe slope of the curve is positive, and the creep damage change rate lambdatiWhen the slope of the curve is negative, a yellow early warning is issued, and the monitoring frequency is enhanced;
when hydrodynamic type damage change rate lambdaiThe slope of the curve is negative, and the creep damage change rate lambdatiThe slope of the curve is negative, and at the moment, the safety of the gravity type dangerous dam dangerous section structure is judged to be within the use requirement range under the combined action of reservoir water level and time change.
2. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 1, wherein the method comprises the following steps: the ST-2000 type acoustic tomography detection system mainly comprises a high-frequency electric spark vibration source and a speed type detector.
3. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 2, wherein the method comprises the following steps: uniformly arranging a plurality of detection points provided with speed detectors on one side surface above the water surface of the dam body, and uniformly arranging monitoring points provided with high-frequency electric spark vibration sources and having the same number as the detection points on the other side surface; and the high-frequency electric spark vibration source descends to the next monitoring point once sounding along the monitoring point until reaching the water surface.
4. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 3, wherein the method comprises the following steps: the position of the dangerous section of the gravity type dangerous dam is judged in a mode that when the envelope curve of the received waveform is semicircular, the section of the position of the speed type detector is judged to be normal; and when the envelope curve of the waveform is in a horn shape, judging that the section of the position where the speed type detector is located is abnormal, and determining the position of the dangerous section of the gravity type dangerous dam according to the abnormal section.
5. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 1, wherein the method comprises the following steps:
gravity typeInitial dynamic elastic modulus E of danger damd0Is determined
When the dam is at low water level, each speed detector receives a received waveform, namely a plurality of longitudinal wave velocities V, after the high-frequency electric spark vibration source sends out a signalPVelocity V of sum transverse waveSTaking the average value of the longitudinal wave velocity and the transverse wave velocity of each normal section, and respectively recording the average value as VPO、VS0Substituting the formula (1) and the formula (2) to obtain the gravity type dangerous dam initial dynamic elastic modulus Ed0。
6. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 1, wherein the method comprises the following steps:
gravity type dangerous dam dangerous section hydrodynamic dynamic elastic die EdiIs determined
The average value V of the wave velocity of the longitudinal wave and the transverse wave received by each velocity type detector of the dangerous section after the water level risespi、VSiSubstituting into formulas (1) and (2) to obtain arbitrary h of dangerous sectioniHydrodynamic dynamic elastic die E of water leveldi。
7. The method for determining the risk of the collapse of the concrete gravity dangerous dam according to claim 1, wherein the method comprises the following steps:
gravity type dangerous dam dangerous section creep dynamic elastic die EdtiIs determined
Under the condition that the reservoir water level is static and unchanged when reaching the peak value, recording the initial static water level t by a speed detector0Average value V of longitudinal wave velocity and transverse wave velocity of dangerous sectionPt0、VSt0And tiAverage value V of longitudinal wave and transverse wave speed received by each speed type detector of time critical sectionPti、VStiCalculating the initial static t after the water level reaches the peak value by the formulas (1) and (2) respectively0And tiMoment dangerous section creep dynamic elastic die Edt0And Edti。
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US5830548A (en) * | 1992-08-11 | 1998-11-03 | E. Khashoggi Industries, Llc | Articles of manufacture and methods for manufacturing laminate structures including inorganically filled sheets |
| US6105430A (en) * | 1998-07-02 | 2000-08-22 | The United States Of America As Represented By The Secretary Of The Interior | Inspection of concrete structures using sonic tomography |
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Non-Patent Citations (2)
| Title |
|---|
| "混凝土重力坝动力系统的可靠性方法研究";徐强;《中国博士学位论文全文数据库 工程科技Ⅱ辑 》;20110531;全文 * |
| "混凝土重力坝在水下冲击波作用下的损伤及防护决策研究";陆路;《中国博士学位论文全文数据库 工程科技Ⅱ辑 》;20131030;全文 * |
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