CN-122017996-A - Slope earthquake motion comprehensive risk assessment method considering three-dimensional coupling of gradient-incident angle-back slope

CN122017996ACN 122017996 ACN122017996 ACN 122017996ACN-122017996-A

Abstract

The invention relates to the technical field of earthquake engineering and geological disaster prevention and control, and discloses a slope earthquake motion comprehensive risk assessment method taking three-dimensional coupling of slope-incidence angle-back slope face into consideration, wherein monitoring points are distributed on the flat land in front of a slope and slope faces on two sides of the slope by constructing a three-dimensional double-sided slope dynamic response model, free field boundaries are arranged around the model, earthquake waves subjected to polynomial baseline correction are input, and peak acceleration amplification coefficients under different slope, incidence angle and slope face orientation conditions are calculated; on the basis, a sensitive incidence angle threshold weight and a back slope facing asymmetric weight are introduced, and a gradient-incidence angle-back slope facing three-dimensional coupling comprehensive risk index is constructed by combining a normalized amplification coefficient, so that unified quantification and grading evaluation of risk intensity under different gradients, different incidence angles and different slope conditions are realized. The method can systematically reveal the coupling rule of the double-sided slope earthquake motion amplifying effect, and provides scientific basis for mountain area engineering earthquake-proof design and regional earthquake damage risk assessment.

Inventors

XIE YUXIN
MAO WENFEI
Lv Changju
WU LIXIN

Assignees

中南大学

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (4)

1. The slope earthquake motion comprehensive risk assessment method considering three-dimensional coupling of gradient-incident angle-back slope is characterized by comprising the following steps: s1, constructing a three-dimensional double-sided slope model, wherein two sides of the slope are symmetrically distributed, and setting the slope height Gradient of And mesh size And define a welcome slope And back slope A rectangular platform representing the flat ground is arranged at the bottom of the slope, and a flat ground reference point is arranged on the platform in front of the welcome slope A plurality of monitoring points are distributed on the slope facing surface and the slope backing surface at equal intervals respectively, wherein the monitoring points on the slope facing surface are marked as The monitoring points on the slope surface are recorded as ; S2, selecting the acceleration time course of the seismic wave As model input load, and before input, performing second order polynomial baseline correction on the original acceleration time course to make the integrated speed and displacement zero at the recording termination time: ; ; Wherein, the In order to correct the function, And In order to correct the coefficient of the coefficient, In order to be able to take time, The corrected acceleration time course; s3, performing power calculation based on three-dimensional quick Lagrange analysis software FLAC3D by adopting an explicit finite difference method, and automatically recording positions of all monitoring points Inputting different incident angles from the bottom of the model when the model performs power calculation Is a seismic wave of (2); S4, respectively calculating monitoring points of the slope and the back slope With a flat ground reference point Where (a) To obtain the ratio of the slope surfaces on two sides Amplification factor: ; Wherein, the Indicating the slope direction; Numbering the monitoring points; S5, calculating sensitive incident angle weights respectively Asymmetric weighting of back slope And normalizing the amplification coefficient, and coupling the three to obtain a comprehensive risk index And performs risk classification accordingly.
2. The method for comprehensively evaluating the risk of the earthquake and vibration on the slope according to claim 1, wherein in the step S1, the model adopts a Mohr-Coulomb constitutive model to simulate the mechanical response characteristics of the slope rock mass under the action of earthquake waves, the model material parameters are set according to the typical mechanical properties of sandstone, a slope surface consistent with the horizontal projection direction of the earthquake waves is defined as a back slope, and a slope surface opposite to the horizontal projection direction of the earthquake waves is defined as a facing slope.
3. The method for comprehensively evaluating the risk of the earthquake motion on the slope according to claim 1, wherein in the step S3, free field boundaries are arranged around the model to avoid obvious reflection or distortion of the upward-propagating earthquake waves at the boundaries, and a Rayleigh damping mode is adopted to represent the energy dissipation characteristic of the system under the action of dynamic load.
4. The method for comprehensively evaluating the risk of the earthquake motion on the slope according to claim 1, wherein the step S5 specifically comprises the following steps: S5.1 for each group With the maximum amplification factor in the group Taking 80% and 90% of the reference as thresholds respectively, and regarding the corresponding incidence angles with the amplification factors within the threshold range as sensitive incidence angles of the slopes; S5.2, based on the two thresholds calculated in the step S5.1, giving corresponding weights of the incidence angles, namely sensitive incidence angle weights, according to the following formula : ; S5.3, for each gradient working condition, respectively taking average values of incident angles on the slope facing surface and the slope backing surface And (3) with Thereby calculating the asymmetric weight of the slope of the facing and backing And wherein: ; ; Wherein, the Is the incident angle The number of groups; =1,2,3... numbering the monitoring points; The number of monitoring points; Is a calibration coefficient; s5.4, dividing the PGA amplification factor by the maximum PGA amplification factor in all conditions Calculating to obtain normalized amplification factor : ; S5.5, the sensitive incidence angle weight obtained according to the steps S5.2, S5.3 and S5.4 Asymmetric weighting of back slope And normalized amplification factor Calculating to obtain gradient-incident angle-back-facing slope three-dimensional coupling comprehensive risk index : ; S5.6, dividing the corresponding slope area into low, medium and high three-level risks according to the size of the comprehensive risk index: 。

Description

Slope earthquake motion comprehensive risk assessment method considering three-dimensional coupling of gradient-incident angle-back slope Technical Field The invention belongs to the technical field of earthquake engineering and geological disaster prevention and control, and particularly relates to a seismic vibration amplification effect evaluation method based on three-dimensional double-sided slope dynamic numerical simulation, in particular to a comprehensive risk index construction method for coupling characterization of slope gradient, seismic wave incident angle and facing/backing slope orientation. Background The mountain slope often shows obvious terrain amplification effect under the earthquake action, and peak acceleration increase phenomenon easily occurs at the slope top and the adjacent areas thereof, so that secondary disasters such as landslide, collapse and the like are induced. The prior art has the following defects: 1. researches are concentrated in a single gradient interval (common 30-60 degrees), and the researches on low-speed and high-steep slopes are insufficient; 2. although the response difference between the double-sided slope welcoming slope and the back slope is observed, the unified quantization index capable of engineering landing is lacking; 3. the incidence angle is obviously influenced by the position of the seismic source and the propagation path, the incidence angle and the gradient are separated and analyzed in the conventional method, the coupling mechanism cannot be reflected, and the risk intensities of different gradients, different incidence angles and different slopes are difficult to compare uniformly. Therefore, a unified evaluation method capable of considering three-dimensional factors of slope-incident angle-slope-face is needed to support engineering earthquake-proof design and mountain earthquake damage evaluation. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a slope earthquake motion comprehensive risk assessment method taking three-dimensional coupling of slope-incident angle-back slope face into consideration, which comprises the steps of constructing a three-dimensional double-sided slope dynamic response model, respectively laying corresponding monitoring points on a flat land in front of the slope and slope faces on two sides of the slope, setting free field boundaries around the model, inputting earthquake waves corrected by base lines, and calculating different slopesIncident angle ofSlope direction(Welcome slope)Back slope) Peak acceleration (PGA) amplification factor below. On the basis, a threshold weight of a sensitive incident angle and an asymmetric weight of a back slope are introduced, a normalized amplification factor is combined, a comprehensive risk index is constructed, gradient-incident angle-back slope three-dimensional coupling risk assessment is realized, and a scientific basis is provided for regional earthquake prevention and disaster reduction. In order to achieve the above purpose, the invention provides a slope earthquake motion comprehensive risk assessment method considering three-dimensional coupling of slope-incident angle-back-facing slope, comprising the following steps: s1, constructing a three-dimensional double-sided slope model, wherein two sides of the slope are symmetrically distributed, and setting the slope height Gradient ofAnd mesh sizeAnd define a welcome slopeAnd back slopeA rectangular platform representing the flat ground is arranged at the bottom of the slope, and a flat ground reference point is arranged on the platform in front of the welcome slopeA plurality of monitoring points are distributed on the slope facing surface and the slope backing surface at equal intervals respectively, wherein the monitoring points on the slope facing surface are marked asThe monitoring points on the slope surface are recorded as; S2, selecting the acceleration time course of the seismic waveAs model input load, and before input, performing second order polynomial baseline correction on the original acceleration time course to make the integrated speed and displacement zero at the recording termination time: ; ; Wherein, the In order to correct the function,AndIn order to correct the coefficient of the coefficient,In order to be able to take time,The corrected acceleration time course; s3, performing power calculation based on three-dimensional quick Lagrange analysis software FLAC3D by adopting an explicit finite difference method, and automatically recording positions of all monitoring points Inputting different incident angles from the bottom of the model when the model performs power calculationIs a seismic wave of (2); S4, respectively calculating monitoring points of the slope and the back slope With a flat ground reference pointWhere (a)To obtain the ratio of the slope surfaces on two sidesAmplification factor: ; Wherein, the Indicating the slope direction; Numbe