Disclosure of Invention
Aiming at the problems, the invention provides the technical scheme that the comprehensive recognition and evaluation method for the collapse risk of the pavement induced by the leakage of methane shallow layer gas comprises the following steps of;
s1, determining the burial depth, the position and the distribution range of shallow gas;
S2, determining the shallow gas leakage rate;
S3, determining the air pressure of the shallow air;
S4, determining reserves of shallow gas;
s5, determining the causative components of shallow air;
s6, introducing a T-S fuzzy model, describing the fault probability of each component in the form of a T-S fuzzy fault tree, more comprehensively considering the fault state, and decomposing and quantifying the complex problem and the uncertainty problem by establishing a T-S fuzzy gate so as to accurately identify and evaluate the pavement collapse risk.
Preferably, the specific steps in S1 include:
S1.1, arranging a parallel electric method testing system according to the difference between a rich gas area in a shallow soil layer and a surrounding medium power supply point field source, wherein the acquisition mode of the parallel electric method testing system is divided into an AM method and an ABM method;
S1.2, adopting a parallel electric method instrument to collect potential difference delta U MN f between two points of a measuring electrode M, N for multiple times, and selecting a group with better data for analysis;
S1.3, integrating the acquired potential difference data, calculating the resistivity rho of the underground geologic body, analyzing by software, inverting the resistivity, outputting ground electric information, and mapping by software.
Preferably, the specific steps in S2 include:
s2.1, arranging an acoustic wave acquisition device at a place where shallow gas is likely to leak, acquiring acoustic wave signals through a multi-channel acoustic sensor, and adopting the frequency spectrum area in a wide frequency band range as a detection index;
S2.2, after wavelet transformation, obtaining wavelet coefficients of each scale from the observed signal, so as to distinguish useful signals with higher wavelet coefficients and noise signals with lower wavelet coefficients, performing threshold denoising processing by adaptively selecting proper threshold functions, repeatedly adjusting the threshold until all noise signals are removed, obtaining estimated values of the wavelet coefficients of each scale of the useful signals, and finally performing inverse transformation to reconstruct signals to obtain useful acoustic signals;
s2.3, analyzing the waveform of the acoustic signal by using an acoustic solver, and calculating the flow velocity characteristics of the leaked gas.
Preferably, the specific step in S3 includes:
S3.1, monitoring and capturing the sonic wave shape of the leakage gas by using a sonic wave sensor;
S3.2, reducing noise generated by other fluctuation in the fluid by using a wavelet analysis method or an Empirical Mode Decomposition (EMD) algorithm;
And S3.3, analyzing the denoised acoustic signals, performing leakage identification by adopting an acoustic-pressure coupling method or various pattern identification algorithms, and calculating shallow air pressure by utilizing lighthill equation characteristics and a finite element method.
Preferably, the specific step in S4 includes:
S4.1, selecting an acquisition mode AM method or an ABM method according to the actual condition of a shallow soil layer field, and arranging a parallel electrical method test system to generate a stable current field in an underground space;
S4.2, carrying out multiple data acquisition by using a parallel electric method instrument, and selecting data with better effect for data processing;
and S4.3, carrying out resistivity inversion according to the acquired data, and comprehensively analyzing shallow gas reserves of the underground space.
Preferably, in S5, the cause component of the superficial gas is analyzed and identified based on the composition and isotope change measurement data of the superficial gas.
Preferably, in S6, the probability of blurring is represented by a trapezoidal membership function.
Preferably, the membership function F is expressed as F= (FO, sl, ml, sr, mr), where F0 is the center of the fuzzy number support set, sl and sr are the left and right support radii, ml and mr are the left and right fuzzy regions. The degree of failure of the fuzzy number F described by the trapezoidal membership function is expressed as:
the invention has the technical effects and advantages that:
1. According to the invention, through integrating various identification indexes and methods of shallow air induced pavement collapse, a fault tree and T-S fuzzy number concept is introduced to express a logic relationship between events, the shallow air leakage induced pavement collapse fault tree is constructed, the sensitivity and importance degree of each factor are evaluated by adopting the T-S fuzzy fault tree, the environmental information of shallow air leakage disasters is comprehensively counted, and accurate risk identification indexes and risk evaluation of shallow air leakage are induced.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention, the objects and other advantages of which are obtained by the structure as set forth hereinafter, as well as the drawings.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. 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.
In the description of the present invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, in the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Embodiment one:
1-3, a comprehensive recognition and evaluation method for risk of collapse of a pavement induced by leakage of methane shallow gas comprises the following steps of;
s1, determining the burial depth, the position and the distribution range of shallow gas;
S2, determining the shallow gas leakage rate;
S3, determining the air pressure of the shallow air;
S4, determining reserves of shallow gas;
s5, determining the causative components of shallow air;
s6, introducing a T-S fuzzy model, describing the fault probability of each component in the form of a T-S fuzzy fault tree, more comprehensively considering the fault state, and decomposing and quantifying the complex problem and the uncertainty problem by establishing a T-S fuzzy gate so as to accurately identify and evaluate the pavement collapse risk.
The specific steps in S1 include:
S1.1, arranging a parallel electric method testing system according to the difference between a rich gas area in a shallow soil layer and a surrounding medium power supply point field source, wherein the acquisition mode of the parallel electric method testing system is divided into an AM method and an ABM method;
S1.2, adopting a parallel electric method instrument to collect potential difference delta U MN f between two points of a measuring electrode M, N for multiple times, and selecting a group with better data for analysis;
S1.3, integrating the acquired potential difference data, calculating the resistivity rho of the underground geologic body, analyzing by software, inverting the resistivity, outputting ground electric information, and mapping by software.
The specific steps in S2 include:
s2.1, arranging an acoustic wave acquisition device at a place where shallow gas is likely to leak, acquiring acoustic wave signals through a multi-channel acoustic sensor, and adopting the frequency spectrum area in a wide frequency band range as a detection index;
S2.2, after wavelet transformation, obtaining wavelet coefficients of each scale from the observed signal, so as to distinguish useful signals with higher wavelet coefficients and noise signals with lower wavelet coefficients, performing threshold denoising processing by adaptively selecting proper threshold functions, repeatedly adjusting the threshold until all noise signals are removed, obtaining estimated values of the wavelet coefficients of each scale of the useful signals, and finally performing inverse transformation to reconstruct signals to obtain useful acoustic signals;
s2.3, analyzing the waveform of the acoustic signal by using an acoustic solver, and calculating the flow velocity characteristics of the leaked gas.
The specific steps in S3 include:
S3.1, monitoring and capturing the sonic wave shape of the leakage gas by using a sonic wave sensor;
S3.2, reducing noise generated by other fluctuation in the fluid by using a wavelet analysis method or an Empirical Mode Decomposition (EMD) algorithm;
And S3.3, analyzing the denoised acoustic signals, performing leakage identification by adopting an acoustic-pressure coupling method or various pattern identification algorithms, and calculating shallow air pressure by utilizing lighthill equation characteristics and a finite element method.
The specific steps in S4 include:
S4.1, selecting an acquisition mode AM method or an ABM method according to the actual condition of a shallow soil layer field, and arranging a parallel electrical method test system to generate a stable current field in an underground space;
S4.2, carrying out multiple data acquisition by using a parallel electric method instrument, and selecting data with better effect for data processing;
and S4.3, carrying out resistivity inversion according to the acquired data, and comprehensively analyzing shallow gas reserves of the underground space.
In S5, the cause component of the shallow gas is analyzed and identified based on the isotope change measurement data of the shallow gas.
In S6, the probability of blurring is represented by a trapezoidal membership function.
Membership function F is represented as f= (F0, sl, ml, sr, mr), where FO is the center of the fuzzy number support set, sl and sr are the left and right support radii, ml and mr are the left and right fuzzy regions. The degree of failure of the fuzzy number F described by the trapezoidal membership function is expressed as:
The method comprises the steps of establishing a proper fault tree, determining that a top event is shallow gas leakage to induce pavement collapse, then determining a direct factor for inducing the top event, giving out a specific logic gate according to a logic relation, repeating the steps until a bottom event, and when the fault tree for inducing the pavement collapse is established, making the following assumption that only shallow gas leakage is considered, wherein the shallow gas leakage is the cause of pavement collapse;
for the road surface subsidence fault tree caused by the shallow air leakage established above, the fault probability and the fault degree are described by using fuzzy numbers in consideration of the fault probability and the logic relationship among the events, and the logic relationship among the events is described by using a T-S fuzzy model. According to the road surface collapse fault tree caused by shallow air leakage, M= (A1, A2, A5), wherein A1, A2, A5 respectively represent each bottom event in the fault tree, M1, M2, M4 respectively correspond to shallow air storage state mutation, underground holes are generated, shallow air leakage is caused, road surface collapse is respectively output by a T-S fuzzy gate 1-4, the common fault degree of A1, A2, A5 and M1, M2, M3 is (0,0.5,1), the membership function is selected as slr=sr=O.1, ml=mr=0.3, the common fault degree of M4 is (0, 1), the membership function is selected as slr=sr=0.25, ml=mr=0.5, and the detailed shallow damage T-S fuzzy gate rule under the action of expansive soil is formulated as follows according to experience;
The related disaster causing factor sensitivity analysis is displayed by the importance degree of each bottom event of the fault tree, when the bottom events have faults with different degrees, the fault probability of the events at the upper part of the system is changed along with the faults, so that the importance degree of the bottom events is measured by the magnitude of the fault probability change of the top events, and the related disaster causing factor sensitivity is analyzed;
according to a road surface subsidence T-S fuzzy fault tree and a fault gate caused by shallow air leakage, carrying out importance analysis on each bottom event A1, A2, and A5, changing the fault probability of a certain bottom event under the condition that other conditions are unchanged, calculating the generated change degree of the fault probability of the top event, further calculating the sensitivity of each related disaster causing factor, and assuming that the fault state of other bottom events is 0.2 and the fault state of a target bottom event is changed step by taking 0.1 as a gradient;
as the fault state of the bottom event increases, the fault probability of the top event increases, but the influence degree of different bottom events on the top event is different, namely the corresponding disaster causing factor sensitivity is different, and each disaster causing factor sensitivity is analyzed as follows:
The influence degree of the cause, the composition and the empirical distribution mode of the bottom event A5 is the greatest, the burial depth, the position and the distribution range of the bottom event A1 are the same, the influence degree of the leakage rate of the bottom event A2, the air pressure of the bottom event A3 and the reserve of the bottom event A4 are the same,
The following relation can be obtained according to the importance thereof:
A5>A1>A2=A3=A4。
Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that modifications may be made to the technical solutions described in the foregoing embodiments or equivalents may be substituted for some of the technical features thereof, and these modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention in essence.