Seismic source/receiver probe for shallow seismic surveying

• US 20070235250A1
• Filed: 03/27/2007
• Published: 10/11/2007
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: Underground Imaging Technologies, Inc. (Caterpillar Incorporated), BBN Technologies (Rtx Corporation)
• Original Assignee: Underground Imaging Technologies, Inc. (Caterpillar Incorporated), BBN Technologies (Rtx Corporation)
• Inventors: Krumhansl, Peter, Whittemore, David
• Granted Patent: US 7,813,224 B2
• Time in Patent Office: Days
• US Class Current: 181/121
• CPC Class Codes: G01V 1/047 Arrangements for coupling the generator to the ground
• CPC Class Codes: G01V 1/09 Transporting arrangements, e.g. on vehicles G01V1/38 takes precedence
• CPC Class Codes: G01V 1/147 using impact of dropping masses
• CPC Class Codes: G01V 1/16 Receiving elements for seismic signals; Arrangements or adaptations of receiving elements
• CPC Class Codes: G01V 1/166 Arrangements for coupling receivers to the ground

Abstract

Systems and methods are implemented for evaluating underground structures and objects, particularly relatively shallow underground structures and objects, using a seismic or acoustic source signal and a resulting seismic or acoustic wave. A discrete or unitary apparatus incorporates both a seismic source transducer and a receiver transducer within a common housing or frame. A unitary seismic probe includes a ground engaging member and a seismic source mechanically coupled to the ground engaging member. The probe further includes a sensor assembly mechanically coupled to the ground engaging member and configured to sense ground vibrations resulting from an impact to the ground engaging member by the seismic source.

Claims

1. A unitary seismic probe, comprising;

a ground engaging member;

a seismic source mechanically coupled to the ground engaging member; and

a sensor assembly mechanically coupled to the ground engaging member and configured to sense ground vibrations resulting from an impact to the ground engaging member by the seismic source.

2. The probe of claim 1, wherein the seismic source comprises a solenoid coupled to a capacitor.

3. The probe of claim 1, wherein the seismic source comprises an anvil configured to be struck by a source of energy and transmit energy resulting from an anvil strike through the ground engaging member.

4. The probe of claim 3, wherein the energy source comprises an activator configured to strike the anvil to generate a seismic or acoustic wave.

5. The probe of claim 3, wherein the energy source comprises a spring biased plunger, positioned away from the anvil in a first state, and configured to cooperate with a solenoid configured to propel the plunger towards the anvil when energized.

6. The probe of claim 1, wherein the ground engagement member comprises a wedge.

7. The probe of claim 1, wherein the ground engagement member comprises a substantially flat portion arranged to contact the ground.

8. The probe of claim 1, wherein the sensor assembly is configured to sense ground vibrations of a type and wavelength appropriate for imaging underground objects to a maximum depth of about 15 feet.

9. The probe of claim 1, wherein the sensor assembly comprises an accelerometer.

10. The probe of claim 1, wherein the sensor assembly comprises a velocity sensor or a geophone.

11. The probe of claim 1, wherein the sensor assembly further comprises:

a generally cylindrical body;

a first end coupled to the ground engaging member; and

a second end comprising;

a generally flat surface for supporting an anvil; and

an aperture for supporting a sensor configured to sense ground vibrations resulting from the impact to the ground engaging member by the seismic source.

12. A seismic sensor array, comprising;

a frame comprising ground supports configured to support the sensor array as it is pulled across the ground;

a plurality of discrete probes, each comprising;

a ground engaging member;

a seismic source mechanically coupled to the ground engaging member; and

a sensor assembly mechanically coupled to the ground engaging member and configured to sense ground vibrations resulting from an impact to the ground engaging member by the seismic source; and

a cross member configured to support pivoting mount arms for each probe so that the discrete probes are maintained in substantially fixed relative locations while allowing the probes to individually contact and engage the ground with a consistent force.

13. The sensor array of claim 12, wherein the mount arms are secured to the frame such that they are isolated from one another both mechanically and electrically.

14. A method of probing the ground, comprising:

contacting the ground with a ground engaging member;

generating a seismic or acoustic probe wave;

transmitting the probe wave into the ground using the ground engaging member; and

sensing, using the ground engaging member, ground vibrations resulting from the transmitted probe wave.

15. The method of claim 14, wherein the probing method facilitates imaging of underground objects to a maximum depth of about 15 feet.

16. The method of claim 14, wherein the probe wave generation and ground vibration sensing facilitate sensing of ground vibrations of a type and wavelength appropriate for imaging underground objects to a maximum depth of 15 feet.

17. The method of claim 14, wherein generating the probe wave comprises generating an impact force of no greater than about 500 lbs peak.

18. The method of claim 14, wherein the generated probe wave provides a response bandwidth to about 3 kHz for depths up to about 15 feet.

19. The method of claim 14, further comprising self-seating the ground engaging member using the probe wave transmitted to the ground engaging member.

20. The method of claim 14 further comprising:

contacting the ground with a plurality of ground engaging members;

generating, for each ground engaging member, a seismic or acoustic probe wave;

transmitting the probe waves into the ground using the plurality of ground engaging members; and

sensing, using each of the ground engaging member, ground vibrations resulting from the transmitted probe waves.

21. The method of claim 20, wherein probe waves are transmitted into the ground using each of the ground engaging members, one at a time, while sensing ground vibrations using some or all of the other ground engaging members.

22. The method of claim 20, further comprising scanning a region of ground by repeating the contacting, generating, transmitting, and sensing processes at each of a plurality of ground locations.

23. The method of claim 22, further comprising:

storing ground vibration sensing data;

recording position data while scanning; and

combining the ground vibration sensing data with the position data to develop a map of the scanned region.

24. A seismic probe, comprising;

a ground engaging member;

a seismic source assembly configured to apply force to the ground engaging member and suspended as to allow vibration of the ground engaging member; and

a seismic receiver assembly mechanically coupled to the ground engaging member, the ground engaging member suspended to permit sensing of ground vibration from an impact generated by the seismic source assembly for evaluating buried objects to a maximum depth of about 15 feet.

25. The seismic probe of claim 24, wherein the seismic source assembly is configured to produce a probe wave that facilitates sensing of ground vibrations of a type and wavelength appropriate for imaging underground objects to the maximum depth of about 15 ft by the seismic receiver assembly.