Method for evaluating deep-buried tunnel blasting parameters

1 . A method for evaluating deep-buried tunnel blasting parameters, comprising:

setting at least two different blasting schemes;

selecting at least two test sections with same geological characteristics, the at least two different blasting schemes corresponding to the at least two test sections, respectively, and a number of the at least two test sections corresponding to a number of the at least two different blasting schemes;

blasting the at least two test sections using the at least two different blasting schemes, respectively, and obtaining various monitoring data of each of the at least two test sections, wherein the various monitoring data include a vector resultant velocity and a risk distance, an unblasted hole rate, a rock wave velocity and a broken rock zone thickness, overbreak and underbreak situations of typical fracture surfaces of the each of the at least two test sections; and

comparing the obtained various monitoring data among the at least two test sections to select an optimal blasting schemes for the at least two test sections;

wherein the obtaining various monitoring data of each of the at least two test sections comprises:

conducting blast vibration monitoring, broken rock zone monitoring, and three-dimensional laser scanning on the at least two test sections;

calculating the vector resultant velocity and the risk distance based on vibration monitoring data obtained from the blast vibration monitoring;

calculating the unblasted hole rate;

calculating the rock wave velocity and the broken rock zone thickness based on acoustic wave test results of broken rock zone monitoring; and

obtaining the overbreak and underbreak situations of typical fracture surfaces based on

3D point cloud data obtained from the three-dimensional laser scanning.

2 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 1 , wherein each of the at least two different blasting schemes comprises an individual-hole charge of each of blastholes of the at least two test sections, a total charge of the blastholes, a blasthole arrangement of the blastholes, a number of the blastholes, and an initiation mode.

3 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 2 , wherein the blastholes comprise cut holes, breaking holes, bottom holes and peripheral holes.

4 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 1 , wherein the length of each of the at least two test sections is 20-50 m.

5 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 1 , wherein calculating the vector resultant velocity and the risk distance based on vibration monitoring data obtained from blast vibration monitoring comprises:

setting a safety allowable vibration velocity v 0 ;

obtaining a terrain condition coefficient K and a geological condition coefficient α; and

substituting the safety allowable vibration velocity v 0 into the Sadaovsk formula

R

0

=

(

K

V

0

)

1

α

⁢

•

⁢

Q

1

3

to obtain a risk distance R 0 , where Q is the total charge of simultaneous blasting or the maximum individual-stage charge of delayed blasting.

6 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 5 , wherein obtaining the terrain condition coefficient K and the geological condition coefficient α comprises:

selecting a first monitoring point in the each of the two test sections, installing a first sensor to monitor particle vibration velocities v x1 , v y1 , and v z1 of the first monitoring point in x, y and z directions, and calculating a vector resultant velocity v 1 of the first monitoring point;

measuring a distance R 1 from the first monitoring point to a heading face;

selecting a second monitoring point in the each of the two test sections, installing a second sensor to monitor particle vibration velocities v x2 , v y2 , and v z2 of the second monitoring point in x, y and z directions, and calculating the vector resultant velocity v 2 of the second monitoring point;

measuring a distance R 2 from the second monitoring point to the heading face; and

substituting v 1 and R 1 into the Sadaovsk formula

R

1

=

(

K

V

1

)

1

α

⁢

•

⁢

Q

1

3

,

and substituting v 2 and R 2 into the Sadaovsk formula

R

2

=

(

K

V

2

)

1

α

⁢

•

⁢

Q

1

3

to form an equation set, so as to obtain the terrain condition coefficient K and the geological condition coefficient α.

7 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 6 , wherein there are five sensors, and the five sensors are sequentially arranged 25 m, 30 m, 35 m, 40 m, and 45 m away from the heading face, so as to fit two curves according to the Sadaovsk formula to obtain the terrain condition coefficient K and the geological condition coefficient α.

8 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 1 , wherein calculating the rock wave velocity and the broken rock zone thickness based on acoustic wave test results of broken rock zone monitoring comprises:

conducting rock wall drilling and water injection to provide a coupling agent needed for testing;

sending a probe of an acoustic wave tester to a bottom of a blasthole, the probe comprising a transmitter and two receivers;

adjusting parameters of the acoustic wave tester;

continuously injecting water into the blasthole, and moving the probe along an axis of the blasthole according to a predetermined sampling interval to collect data separately, so as to obtain rock wave velocities at different depths from a surrounding rock wall; and

plotting a depth-wave velocity curve according to the rock wave velocities, and obtaining the broken rock zone thickness.

9 . The method for evaluating the deep-buried tunnel blasting parameters according to claim 1 , wherein comparing the obtained various monitoring data to select the optimal blasting schemes for the at least two test sections comprises:

comparing vector resultant velocities of the at least two different blasting schemes and selecting a blasting scheme with a smaller vector resultant velocity;

comparing risk distances of the at least two different blasting schemes and selecting a blasting scheme with a smaller risk distance;

comparing unblasted hole rates of the at least two different blasting schemes and selecting a blasting scheme with a larger unblasted hole rate;

comparing broken rock zone thicknesses of the at least two different blasting schemes, and selecting a blasting scheme with a smaller broken rock zone thickness;

comparing overbreak and underbreak situations of the at least two different blasting schemes, and selecting a blasting scheme with less overbreak and underbreak; and

conducting comprehensive evaluation on the selected blasting schemes to determine the optimal blasting schemes for the at least two test sections.