CN105604557B - Shield-tunneling construction boulder detection method based on earthquake CT - Google Patents

Abstract

A method for detecting boulders in shield construction based on seismic CT, comprising: arranging a first drilling channel group and a second drilling channel group on a shield machine cutterhead; Drill a transmitting hole and a receiving hole of the same length in front of the disk; excite the transmitter in the transmitting hole, perform multi-point reception by several receivers in the receiving hole, perform seismic CT imaging, collect and process the seismic waveform data, and draw the velocity distribution Judging whether there is a boulder from the velocity distribution map. The invention has simple steps and convenient operation. The seismic CT imaging is performed in front of the shield machine, the distance between the transmitter and the receiver is short, the moving distance is small, the resolution is high, and the boulder in front of the shield construction can be effectively detected; Drilling images may be drilled at the lone stone in front, which is highly targeted, avoids invalid construction, and significantly reduces construction costs.

Description

Boulder detection method for shield construction based on seismic CT

technical field

The invention specifically relates to a method for detecting boulders in shield construction based on seismic CT.

Background technique

In the southern coastal areas of my country, boulders are often encountered in the construction of subway shields, which are weathered cores left by uneven weathering of granite. Boulders may bring major safety hazards and must be identified before shield machine construction. Drilling and geophysical prospecting methods are important means to detect boulders. Both methods are usually carried out on the surface. By drilling multiple boreholes above the shield construction tunnel, vertical intensified detection is carried out to determine the location, shape and size of boulders. Then carry out deep hole blasting. There are serious problems in using surface drilling to detect boulders. Not only does it require a large number of holes, but it is also easily restricted by conditions such as buildings and pipelines. Vertical drilling in rivers is costly and complicated, and it is difficult to find boulders. Accurate positioning will ultimately affect the blasting effect.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for detecting boulders in shield construction based on seismic CT.

The present invention is achieved in that a method for detecting boulders in shield construction based on seismic CT comprises the following steps:

(1) Hole arrangement on the cutter head of the shield machine: the first drilling channel group and the second drilling channel group are arranged on the shield machine cutter head; the first drilling channel group is located in the second drilling channel group Inside, the first drilling channel group includes three first drilling channels, and the three first drilling channels are evenly distributed on the circle C1 with the center of the cutterhead as the center; the second drilling channel group Including six second drilling passages, and the six second drilling passages are evenly distributed on the circle C2 with the center of the cutter head as the center;

(2) Drilling in front of the shield machine: In the shield construction tunnel, through the first drilling channel and the second drilling channel on the cutter head, the casing wall is used, and the advanced drilling machine is used to drill the shield from the back to the front. 9 detection holes with the same length are drilled in front of the machine cutterhead, and the length of the detection holes is greater than the distance between the circle C1 and the circle C2; the detection hole corresponding to the first drilling channel is an emission hole, and the second The detection hole corresponding to the drilling channel is the receiving hole;

(3) Seismic CT imaging: a transmitter is fixed on the top of a hollow first metal rod, the top of the first metal rod extends into a transmission hole, and the tail of the first metal rod is inserted into the first In the drilling channel; a plurality of receivers are spaced and evenly fixed on a hollow second metal rod, the part of the second metal rod corresponding to the receiver extends into the receiving hole, and the tail of the second metal rod is inserted into the The second drilling channel of the cutter head; the transmitter and the receiver are both connected to a host computer through cables;

Excite the transmitter in the transmitting hole, and perform multi-point reception by multiple receivers in the receiving hole; among them, a group of receivers are installed in the 6 receiving holes at the same time, and the receiving observation is carried out at the same time; or the 6 receiving holes are carried out in batches Receive observation; after completing an excitation, check the complete situation of the seismic waveform and the take-off of the first arrival wave from the host computer; after completing all the launches in one launch hole, move the first metal pole and the transmitter to another launch hole, Continue to collect seismic waveform data until the waveform data collection of all transmitting holes and receiving holes is completed; process the collected seismic waveform data, draw a velocity distribution map, and judge whether there is a boulder from the velocity distribution map.

Further, the radius of the circle C1 is 1-1.5m, and the distance between the circle C2 and the outer edge of the cutterhead is 0.5m.

Further, the length of the detection hole is 20m, and the diameter of the hole is 90mm.

Further, in the step (2), when the detection hole is drilled, it must be inclined 5°-10° along the axial direction of the shield construction tunnel, and the detection hole must be filled with water and always filled with water.

The present invention has the advantages of simple steps and convenient operation, seismic CT imaging is performed in front of the shield machine, the distance between the transmitter and the receiver is short, the moving distance is small, the resolution is high, and the isolated area in front of the shield machine can be effectively detected. Stone; There may be a lone stone in front of the shield machine to drill and image, which is highly targeted, avoids invalid construction, and significantly reduces construction costs.

Description of drawings

The present invention will be further described below in conjunction with the embodiments with reference to the accompanying drawings.

Fig. 1 is the construction flowchart of the boulder detection method for shield construction based on seismic CT in the present invention.

Fig. 2 is a schematic structural view of the cutter head of the shield machine in the present invention.

Fig. 3 is a structural schematic diagram of a tunnel constructed by shield tunneling in the present invention. .

Fig. 4 is a matching diagram of the transmitter and the first metal rod in the present invention.

Fig. 5 is a matching diagram of the injector and the second metal rod in the present invention.

Fig. 6 is a working principle diagram of seismic CT in the present invention.

Detailed ways

Please refer to Figure 1-3, a seismic CT-based method for boulder detection in shield construction, including the following steps:

(1) Hole distribution on the cutter head of the shield machine: the first drilling channel group 2 and the second drilling channel group 3 are arranged on the shield machine cutter head 1; the first drilling channel group 2 is located in the second drilling channel group Inside the hole channel group 3, the first drilling channel group 2 includes three first drilling channels 21, and the three first drilling channels 21 are evenly distributed on the circle C1 with the center of the cutterhead 1 as the center The second drilling channel group 3 includes six second drilling channels 31, and the six second drilling channels 31 are evenly distributed on the circle C2 with the center of the cutterhead 1 as the center; the circle C1 The radius of the circle C2 is 1-1.5m, and the distance d between the circle C2 and the outer edge of the cutterhead 1 is 0.5m.

(2) Drilling in front of the shield machine: In the shield construction tunnel 12, through the first drilling channel 21 and the second drilling channel 31 on the cutter head 1, a casing (not shown) is used to protect the wall, and the advanced The drilling machine (not shown) drills 9 detection holes with the same length in front of the shield machine cutter head 1 from back to front, and the length of the detection holes is greater than the circle C1 and circle C2 (the first drilling channel 21 and the circle C2). The distance between the hole spacing) between the second drilling channels 31; the length of the detection hole is 20m, and the aperture is 90mm. Among them, when drilling, it is necessary to incline 5° to 10° along the axial direction of the shield construction tunnel 12 (it cannot simply be drilled along the horizontal direction), and water must be poured into the detection hole to ensure that the detection hole is always full. Water, so that the seismic wave can effectively propagate from the hole wall to the instrument and reduce attenuation; the detection hole corresponding to the first drilling channel 21 is the transmitting hole 4, and the detection hole corresponding to the second drilling channel 31 is the receiving hole 7. The casing wall is used to effectively ensure the quality of the hole, which can prevent the hole from collapsing and the hole from being stuck.

(3) Seismic CT imaging: a transmitter 5 is fixed on the top of a hollow first metal rod 6, the top of the first metal rod 6 extends into a launch hole 4, and the tail of the first metal rod 6 is inserted into the In the first drilling channel 21 of the cutter head 1; a plurality of receivers 8 are spaced and evenly fixed on a hollow second metal rod 9, and the part of the second metal rod 9 corresponding to the receiver 8 extends into a receiving hole 7, and the tail of the second metal rod 9 is inserted into the second drilling channel 31 of the cutter head 1; the transmitter 5 and the receiver 8 are connected to a host computer 11 through a cable 10, and the cables 10 should be hidden into the inside of the first metal rod 6 and the second metal rod 9, as shown in Figure 4-5.

As shown in Figure 6, the transmitter 5 in the transmitting hole 4 is excited, and the plurality of receivers 8 in the receiving hole 7 will perform multi-point reception; wherein, a group of receivers 8 can be respectively installed in the six receiving holes 7 at the same time , and receive and observe at the same time; or conduct receiving and observing in batches with 6 receiving holes 7; after completing one excitation, check the complete situation of the seismic waveform and the take-off situation of the first arrival wave from the host computer 11; complete all transmissions in one transmitting hole 4 Finally, move the first metal rod 6 and the transmitter 5 to another transmission hole 4, and continue to collect seismic waveform data until completing the waveform data collection of all transmission holes 4 and receiving holes 7; Processing, eliminating errors, using man-machine combination to pick up the travel time of the first arrival wave, establish a travel time library, analyze the velocity distribution according to the picked travel time library and combined with known engineering geological data, and establish an initial velocity model; use curved ray Tracing method, draw a ray distribution diagram, check whether the rays are traced correctly, analyze the sparseness of the rays, draw a velocity distribution diagram, mark the abnormal speed area, and judge whether there is a boulder from the velocity distribution diagram. Since the boulder belongs to the weathering core left by uneven weathering of granite, there is a wave velocity difference between the boulder and the surrounding medium, which is generally significantly higher than that of the surrounding medium. This wave velocity difference can be explained in combination with known geological or engineering data. Judging whether there is a lone rock in the velocity distribution map drawn by seismic CT.

(4) Boulder blasting

If it is found that there is a boulder in front of the shield machine, blasting will be carried out according to the location, shape and size of the boulder to ensure the safe construction of the shield machine.

The invention has simple steps and convenient operation. The seismic CT imaging is performed in front of the shield machine, the distance between the transmitter and the receiver is short, the moving distance is small, the resolution is high, and the boulder in front of the shield construction can be effectively detected; Drilling images may be drilled at the lone stone in front, which is highly targeted, avoids invalid construction, and significantly reduces construction costs.

Claims (3)

1. A kind of 1. shield-tunneling construction boulder detection method based on earthquake CT, it is characterised in that：Comprise the following steps：

   (1) cloth hole on cutter head of shield machine：The first drilled tunnel group and the second drilled tunnel group are laid on cutter head of shield machine；It is described First drilled tunnel group is located at the inside of the second drilled tunnel group, and the first drilled tunnel group includes three the first drilled tunnels, And three first drilled tunnels are evenly distributed on using cutter head center as on the circle C1 in the center of circle；The second drilled tunnel group bag Six the second drilled tunnels are included, and six second drilled tunnels are evenly distributed on using cutter head center as on the circle C2 in the center of circle；

   (2) drilled in front of shield machine：It is logical by the first drilled tunnel on cutterhead and the second drilling in shield-tunneling construction tunnel Road, using sleeve pipe retaining wall, drill through 9 length identical exploration holes in front of cutter head of shield machine from the front to the back with advanced rig, and The length of exploration hole is more than the spacing between the round C1 and circle C2；Exploration hole corresponding to first drilled tunnel is transmitting Hole, the exploration hole corresponding to the second drilled tunnel are receiver hole；

   It in the step (2), when drilling through exploration hole, must have a down dip 5 °~10 °, and detect along the axis direction in shield-tunneling construction tunnel It must be poured water in hole and be full of water all the time；

   (3) earthquake CT is imaged：One transmitter is fixed on a first hollow metallic rod top, the first metallic rod top stretches into one In launch hole, and the afterbody of first metallic rod is inserted in the first drilled tunnel of cutterhead；By a plurality of receiver intervals and Uniformly it is fixed in a second hollow metallic rod, the part that the second metallic rod corresponds to receiver is stretched into receiver hole, and the The afterbody of two metallic rods is inserted in the second drilled tunnel of cutterhead；The transmitter and receiver pass through cable and a host computer Connection；

   Transmitter in excitation-emission hole, multipoint reception is carried out by a plurality of receivers in receiver hole；Wherein, in 6 receiver holes 1 receivers is installed respectively simultaneously, while carries out reception observation；Or reception observation is conducted batch-wise in 6 receiver holes；Complete once After exciting, the complete situation of seismic waveform and preliminary wave take-off situation are checked from host computer；Institute is completed in a launch hole After having transmitting, the first metallic rod and transmitter are moved on in another launch hole, continue to gather seismic waveform data, until completing institute There is the collection of the Wave data of launch hole and receiver hole；The seismic waveform data gathered is handled, draws velocity contour, Boulder is judged whether from velocity contour.
2. 2. the shield-tunneling construction boulder detection method based on earthquake CT as claimed in claim 1, it is characterised in that：The round C1's Radius is 1~1.5m, and the distance between outward flange of the round C2 and cutterhead is 0.5m.
3. 3. the shield-tunneling construction boulder detection method based on earthquake CT as claimed in claim 1, it is characterised in that：The length of exploration hole Spend for 20m, aperture 90mm.