Compound penetration and micro-tunneling instrument and method

Abstract

An exemplary instrument and method are disclosed for (i) penetrating soil or soil-based materials with minimal disturbance and reaction forces, and (ii) determining the characteristics and properties of the soil or soil-based materials by measuring the forces and torques required for the penetration or micro-tunneling.

Description

COMPOUND PENETRATION AND MICRO-TUNNELING INSTRUMENT AND METHODGovernment License Rights

[0001] This invention was made with government support under 1935548, awarded by the National Science Foundation. The government has certain rights in the invention.Related Application

[0002] This PCT application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 63 / 663,490, filed June 24, 2024, entitled ‘COMPOUND CENTIPEDEROOT-VORTEX INSPIRED PENETRATION DEVICES AND MECHANISMS,” which is incorporated by reference herein in its entirety .Background

[0003] Soil penetration is encountered in geotechnical engineering for various purposes and at different scales, such as when installing deep foundations (e.g., piles), conducting tunneling activities (e g., pipe-jacking and micro-tunneling), or using in-situ testing methods (e.g., the cone penetration test, dilatometer test). When a penetrating body is advanced into the ground using static or dynamic forces, the body can encounter penetration resistance. The penetration resistance comes from the force needed at the tip of the body to expand the cavity and the friction developed on the sides at the interface between the penetrating body and the soil.

[0004] Cone Penetration Testing (CPT) is a geotechnical investigation method used to assess subsurface soil conditions. It involves pushing a cone-shaped (probe) into the ground and measuring the resistance at the tip and along the sides (sleeve) of the probe. This data helps determine soil type, density, strength, and other properties.

[0005] The standard penetration test (SPT) is an in-situ dynamic penetration test designed to provide information on the geotechnical engineering properties of soil. This test is the most frequently used subsurface exploration drilling test. The test provides for the identification and measurement of penetration resistance, e.g., geotechnical evaluation applications.

[0006] There is a benefit to improving available soil-penetrating instruments and methods in geotechnical engineering.Summary

[0007] An exemplary' soil-penetrating instrument and method are disclosed for (i) penetrating soil or soil-based materials using an optimized drill tip with vortex component to minimize or reduce disturbance and reaction forces, and (ii) determining the characteristics and properties of the soil or soil-based materials by measuring the forces and torques required for the penetration.

[0008] In some implementations, the instrument comprises (i) a drill tip having a vortex or helical shape with an apex angle of 30-60 degrees and a pitch of D to 6D (where D is the tip base diameter in millimeters) per revolution (preferably 2D-3D mm / rev), (ii) at least two actuators (e.g., stepper motors) independently controlling the drill tip: one configured to provide linear axial motion (e.g., at a rate of axial displacement) and the other to provide rotational motion (e.g.. at another rate of rotational motion), both via a longitudinal shaft, and (iii) a sensor (e.g., torque-force sensor) configured to measure the axial force and torque applied to the drill tip, by the actuators, during soil penetration.

[0009] Current small-scale soil penetration methods, those using small drill tips / probes (e.g., cone penetrometers), rely on a direct axial push to advance the probe into the soil. While widely used, these methods can cause soil displacement and disturbance. As the dnll tip / probe penetrates, the drill tip / probe can displace soil both laterally and forward, creating a disturbed zone that can extend to a diameter 16 times that of the drill tip / probe. This disturbance can alter the in-situ soil conditions and contribute to increased penetration resistance due to both tip / probe resistance and side friction.

[0010] Current large-scale tunneling systems (e g., micro-tunneling, tunnel boring) employ active soil removal at the face of penetration by utilizing cutter heads to fragment the soil and transporting the fragmented soil away. While effective at minimizing soil displacement and reducing resistance, these large-scale systems are complex, costly, and impractical for smaller-scale applications or in situ soil testing scenarios.

[0011] The exemplary instrument can address the limitations of both current small-scale penetration methods and large-scale tunneling systems, by reducing frictional resistance at the drill tip / probe and minimizing soil disturbance, through a combination of mechanical design (of the drill tip) and independent actuation (of the actuators / motors). By modifying the interaction between the drill tip and the surrounding soil, the exemplary' instrument can enhance penetration efficiency, reduce energy' consumption, and preserve the integrity of the soil structure.

[0012] The exemplary instrument is advantageous in geotechnical testing and construction applications where maintaining undisturbed soil conditions is critical foraccurate data collection or structural stability. Furthermore, reducing the required penetration force can enable the use of lighter, more portable equipment, thereby expanding the applicability of the instrument to a wider range of field conditions and environments.

[0013] In an aspect, an instrument for a penetration test is disclosed comprising: a longitudinal shaft; a drill tip disposed at a first instrument end (e.g., soil-excavating end) of the penetration test instrument and connected to the longitudinal shaft, wherein the drill tip is configured to axially and rotationally penetrate soil for soil analysis; a first actuator operatively coupled to the drill tip through the longitudinal shaft, wherein the first actuator is configured to move, in a linear motion (e.g., downward), the drill tip from a first position in a first configuration to a second position in the soil; a second actuator operatively coupled to the drill tip and the first actuator, wherein the second actuator is configured to rotate the drill tip while the drill tip is being moved into the soil; and a force-torque sensor operatively coupled to the drill tip, wherein the sensor is configured to independently measure force and torque that the first and second actuators are required to apply to the drill tip while moving the rotating into the soil, and wherein the measured force and torque are outputted in a report to subsequently determine characteristics and properties of the soil.

[0014] In some embodiments, the instrument described herein further comprises: a set of supports configured to mount and anchor the instrument for a given position for soil measurement.

[0015] In some embodiments, the drill tip, the first and second actuators, and the sensor are aligned w ith each other and arranged to be parallel to a longitudinal axis of the drill tip.

[0016] In some embodiments, the linear motion is parallel to the longitudinal axis of the drill tip.

[0017] In some embodiments, the drill tip has an apex angle varied between 30 and 60 degrees, and wherein the drill tip is attachable and reattachable for different soil types for a respective apex angle.

[0018] In some embodiments, the drill tip has a pitch varied between 1 and 6 times the diameter (D) of the drill tip, and wherein the drill tip is attachable and reattachable for different soil types for a respective pitch.

[0019] In some embodiments, the force-torque sensor is positioned on the longitudinal shaft.

[0020] In some embodiments, the force-torque sensor is integrated into the drill tip.

[0021] In some embodiments, the drill tip comprises: a longitudinal frame around a central shaft with a set of rollers attached to it; a set of rollers attached to the longitudinalframe; and one or more track belts, supported by the rollers, configured to revolve along a path aligned with the longitudinal frame (e.g.. the one or more track belts revolve around, thereby pushing the soil excavated by the drill tip to a second instrument end).

[0022] In some embodiments, the drill tip and longitudinal frame have at least one shape of a square pyramid, cross-based pyramid, hexagonal pyramid, circular pyramid, and vortical pyramid.

[0023] In some embodiments, the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged to be parallel to a longitudinal axis of the frame.

[0024] In some embodiments, the one or more track belts and a portion of the set of rollers are aligned with each other, and the one or more track belts and the portion of the set of rollers are arranged in a helical manner with respect to a longitudinal axis of the frame.

[0025] In some embodiments, each of the first and second actuators is a stepper motor controlled by a motor driver.

[0026] In another aspect, an instrument for micro-tunneling is disclosed comprising: a longitudinal shaft; a drill tip disposed at a first instrument end (e.g.. soil-excavating end) and connected to the longitudinal shaft, wherein the drill tip is configured to axially and rotationally excavate soil; a first actuator operatively coupled to the drill tip through the longitudinal shaft, wherein the first actuator is configured to move, in a linear motion (e.g., horizontally), the drill tip from a first position in a first configuration to a second position in the soil; a second actuator operatively coupled to the drill tip and the first actuator, wherein the second actuator is configured to rotate the drill tip while the drill tip is being moved into the soil; and a force-torque sensor operatively coupled to the drill tip, wherein the sensor is configured to independently measure force and torque that the first and second actuators are required to apply to the drill tip while moving the rotating to excavate the soil, and wherein the measured force and torque are outputted in a report to subsequently adjust motor controls and advancement rate.

[0027] In some embodiments, the instrument described herein comprises: a set of supports configured to mount and anchor the instrument for a given position for soil measurement.

[0028] In some embodiments, the drill tip, the first and second actuators, and the sensor are aligned with each other and arranged to be parallel to a longitudinal axis of the drill tip.

[0029] In some embodiments, the linear motion is parallel to the longitudinal axis of the drill tip.

[0030] In some embodiments, the drill tip has an apex angle varied between 30 and 60 degrees, and wherein the drill tip is attachable and reattachable for different soil types for a respective apex angle.

[0031] In some embodiments, the drill tip has a pitch varied between one and 6 times the diameter (D) of the drill tip, and wherein the drill tip is attachable and reattachable for different soil types for a respective pitch.

[0032] In some embodiments, the force-torque sensor is positioned on the longitudinal shaft.

[0033] In some embodiments, the force-torque sensor is integrated into the drill tip.

[0034] In some embodiments, the drill tip comprises: a longitudinal frame around a central shaft with a set of rollers attached to it; a set of rollers attached to the longitudinal frame; and one or more track belts, supported by the rollers, configured to revolve along a path aligned with the longitudinal frame (e.g., the one or more track belts revolve around, thereby pushing the soil excavated by the drill tip to a second instrument end).

[0035] In some embodiments, the drill tip and longitudinal frame have at least one shape of a square pyramid, cross-based pyramid, hexagonal pyramid, circular pyramid, and vortical pyramid.

[0036] In some embodiments, the one or more track belts and a portion of the set of rollers are aligned with each other, and the one or more track belts and the portion of the set of rollers are arranged to be parallel to a longitudinal axis of the frame.

[0037] In some embodiments, the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged in a helical manner with respect to a longitudinal axis of the frame.

[0038] In some embodiments, each of the first and second actuators is a stepper motor controlled by a motor driver.Brief Description of Drawings

[0039] Figs. 1A - IB each shows an example instrument / device for a penetration test (also referred to as a penetration test instrument) for determining the characteristics of a soil, or soil-based material, using (i) at least two actuators configured to apply, via a longitudinal shaft, linear and rotational motions to a drill tip so that the drill tip can penetrate the soil (shown as ground), or soil-based material, and (ii) a sensor (e g., torque-force sensor, pressure transducer) configured to measure force and torque the two actuators apply to the drill tip while the drill tip is penetrating the soil, or soil-based material, which can be storedin a datalogger and subsequently used to determine characteristics of the soil, or soil-based material, in accordance to an illustrative embodiment.

[0040] Figs. 2A - 2B each shows an example drill tip having a vortical shape / surface with various apex angles and pitches, without a moving belt.

[0041] Figs. 2C - 2G each shows an example drill tip having (i) one or more track belts and (ii) a top portion.

[0042] Figs. 3A - 3B each shows an operation flow, employing the exemplary instrument, for each of the penetration testing and micro-tunneling operations.

[0043] Figs. 4A - 4B show (i) an experimental setup for evaluating, via X-ray scans and three-dimensional (3D) digital image correlation (DIC). an experimental instrument and (ii) configurations (e.g., sizes, angles) for each of the components (e.g., sensor, actuate rs / stepper motors, motor driver, data acquisition logger, drill tip without a moving belt) in the experimental instrument.

[0044] Figs. 4C - 4D show' 3D image of (i) a soil-based material / specimen (e.g., sand) and (ii) the drill tip penetrating the soil-based material / specimen.

[0045] Fig. 4E shows the rotation speed (RS) and pitch-compatible speed (PCS) for 4 drill tips, in 12 scenarios, having different combinations of apex angles and pitches.

[0046] Fig. 4F shows X-ray images of the drill tip, of the experimental instrument, penetrating the soil-based material / specimen at different RS and PCS.

[0047] Fig. 4G shows a continuum-based analysis, on the X-ray images in Fig. 4F. to assess the disturbance caused by the penetration of the drill tip into the soil-based material / specimen.

[0048] Figs. 4H - 4K show' reaction force measurements, torque measurements, and total energy measurements as a function of the ratio of rotation and axial speeds.

[0049] Fig. 5 show s another experimental setup and digital image correlation (DIC) analysis used to evaluate the track belt of another experimental instrument.

[0050] Fig. 6 shows a micro-tunneling device / unit used in a field micro-tunneling operation.Detailed Description

[0051] Some references, which may include various patents, patent applications, and publications, are cited in a reference list and discussed in the disclosure provided herein. The citation and / or discussion of such references is provided merely to clarify the description of the disclosed technology and is not an admission that any such reference is “prior art” to anyaspects of the disclosed technology described herein. In terms of notation, “[n] ” corresponds to the nth reference in the list. For example, [1] refers to the first reference in the list. All references cited and discussed in this specification are incorporated herein by reference in their entirety and to the same extent as if each reference were individually incorporated by reference.

[0052] Example Instrument / Device

[0053] Figs. 1A - IB each shows an example instrument / device for a penetration test 100 (shown as 100a, 100b) (also referred to as a penetration test instrument) for determining the characteristics of a soil, or soil-based material, using (i) at least two actuators (e.g., 102, 104) configured to apply, via a longitudinal shaft 108, linear and rotational motions (e.g., 103, 105) to a drill tip 110 (shown as 110') (also referred to as a probe) so that the drill tip 110 can penetrate the soil (shown as ground), or soil-based material, and (ii) a sensor 106 (shown as 106’) (e.g., torque-force sensor, pressure transducer) configured to measure force and torque the two actuators (e.g., 102, 104) apply to the drill tip 110 while the drill tip 110 is penetrating the soil, or soil-based material, which can be stored in a datalogger 122 (shown as 122’) and subsequently used to determine characteristics of the soil, or soil-based material.

[0054] Actuators (102, 104). In the examples shown in Figs. 1A - IB, the actuators 102 (shown as 102', #1) and 104 (shown as 104', #2) can be operatively coupled to the longitudinal shaft 108. Each of the actuators can independently control (e.g., move or rotate), through the longitudinal shaft 108, the drill tip 110, because the drill tip 110 is connected to the longitudinal shaft 108 at the ground-penetrating end of the instrument 100a - 100b. The longitudinal shaft 108 can be held stable using bearings 112 (shown as 112’), while the actuators are controlling (e.g., moving, rotating), via the shaft 108, the drill tip 110.

[0055] The actuator 102 can be operatively coupled to the longitudinal shaft 108 using a screwjack 116 (shown as 116’). The actuator 102, controlled by its motor driver, can push, via the shaft 108 and in the linear motion 103 (e.g., downw ard), the drill tip 110 deeper into the soil or soil-based material. The axial force that the actuator 102 applies to the drill tip 110 to push the drill tip 110 deeper into the soil or soil-based material can be measured by the sensor 106 and subsequently stored in the datalogger 112. The actuator 102 can be optionally connected to a linear guide 118 (shown as 118’) to maintain the linear motion 103 parallel to the longitudinal axis of the drill tip 110 (i.e., move dow n, minimizing deviation). In some embodiments, the actuator 102 is a torsional stepper motor.

[0056] The actuator 104. also controlled by its motor driver, can rotate (see 105), via the shaft 108, the drill tip 110, while the drill tip 110 is being pushed deeper into the soil or soil-based material by the actuator 102. The torque the actuator 104 generates when rotating the drill tip 110 can also be measured by the sensor 106 and subsequently stored in the datalogger 112. In some embodiments, the actuator 104 is an axial / rotational stepper motor.

[0057] Each of the motor drivers of the actuators 102 and 104 can be controlled by a global controller 120 (shown as 120’). The actuators 102-104, the sensor 106, and the drill tip 110 can be aligned with each other and arranged to be parallel to the longitudinal axis of the drill tip 1 10.

[0058] Sensor (106) and Anchor (114). In the examples shown in Figs. 1A - IB, the sensor 106 (e.g., torque-force sensor, pressure transducer) is configured to measure (i) the force that the actuator 102 applies, via the shaft 108, to the drill tip 110 to push the tip 110 into the soil or soil-based material, and (ii) the torque that the actuator 104 generates to rotate the drill tip 1 10 when the drill tip is being pushed, by the actuator 102, deeper into the soil or soil-based material. The sensor 106 can then store the measured axial force and torque in the datalogger 122, allowing them to be output as a report to subsequently determine the characteristics of the soil or soil-based material.

[0059] Different types of soils exhibit distinct characteristics that can be determined by force and torque measurements from sensor 106. If the soil or soil-based material is soft clay, then the measured axial force can be low' and the measured torque can be high, because there can be a bond betw een the clay and the drill tip 110. If the soil or soil-based material is dense sand, the measured axial force can be high, and the measured torque can be low.

[0060] In some embodiments, the instrument lOOa-l OOb has a set of supports (e g., stand anchor 114, shown as 114’) configured to mount and anchor the instrument to a position on the soil or soil-based material, to prevent the instrument from falling when experiencing reaction force, from the soil or soil-based material, to the soil-penetrating force / torque from the drill tip 1 10.

[0061] In Fig. 1A, the sensor 106 is positioned on the longitudinal shaft 108, in proximity to one of the actuators 102-104. In Fig. IB, the sensor 106 is integrated, at the soilpenetrating end of the instrument 100b, into the drill tip 110. The sensor 106 is also configured to withstand high pressure when the drill tip 110 is penetrating deeply (e.g., up to 50 feet) into the soil or soil-based material.

[0062] Drill Tip (110). Figs. 2A - 2B each show's an example drill tip 110 having a vortical shape / surface with varied apex angles and pitches. The drill tip 110 can be attachable and reattachable for different soil types for a respective apex angle or pitch.

[0063] In the example shown in Fig. 2A, the drill tip 110 has a vortical shape so that it can effectively penetrate the soil or soil-based material 201 when being moved (i) in a linear motion 103 by an actuator (see 102, Figs. 1A - IB), and (ii) in rotational motion 105 by another actuator (see 104, Figs. 1A - IB). Diagrams 202 and 204 show example vertical and horizontal particle displacement fields, in the soil or soil-based material, as a function of the ratio of axial displacement speed to pitch-compatible speed, respectively, when the drill tip 110 is penetrating the soil or soil-based material. Diagrams 202 and 204 were determined from an upward image in the experimental setup of the study.

[0064] In Fig. 2B, the vortical-shaped drill tip can have varied (i) apex angles (e.g., 30 - 60 degrees) and (ii) pitches (e.g., 1 - 6 times the diameter of the drill tip 110, e.g., 1-100 per revolution (mm / rev)). Each apex angle can provide the drill tip with a respective rotation speed, and each pitch can provide the drill tip with a respective pitch-compatible speed, when the drill tip is penetrating the soil or soil-based material.

[0065] Figs. 2C - 2G each shows an example drill tip 110 having (i) one or more track belts 210 (shown as 210’) and (ii) a top portion 214 (shown as 214').

[0066] In the example shown in Fig. 2C - 2G. the dnll tip 110 can have a longitudinal frame 206 (shown as 206’) around a central shaft 208 (shown as 208’) (e.g., 108, Figs. 1 A - IB). The longitudinal frame 206 can have a first frame end and a second frame end, and can form various hollow shapes (e.g., square pyramid, cross-based pyramid, hexagonal pyramid, circular pyramid, vortical pyramid).

[0067] A set of rollers 212 (shown as 212’) can be (i) operatively attached to one or more sides of the frame 206, along a longitudinal axis of the frame 206 from the first frame end to the second frame end, and (ii) rotated by a motor 216 disposed at either end of the frame 206. One or more track belts 210 can (i) be supported by the set of rollers 212 and (ii) revolve along a path aligned with the frame 206.

[0068] The top portion 214 can have a cross-sectional shape of a pentahedron (i.e., square pyramid), a cross-based pyramid, a heptahedron (i.e., hexagonal pyramid), a cone, or a vortex.

[0069] In one embodiment, one or more track belts 210 and the set of rollers 212, or a portion thereof, can be aligned with each other and arranged to be parallel to the longitudinal axis of the frame 206. In another embodiment, one or more track belts 210 and the set of rollers 212. or a portion thereof, can be aligned with each other and arranged in a helical manner with respect to the longitudinal axis of the frame 206.

[0070] Example Operation Flow-

[0071] The exemplary instrument / device can be employed for soil penetration testing and micro-tunneling operations. Figs. 3A - 3B each shows an operation flow 300 (shown as 300a, 300b), employing the exemplary instrument / device (see Figs. 1 A - IB), for each of the penetration testing and micro-tunneling operations.

[0072] In the example shown in Fig. 3A, the method 300a includes two phases: data acquisition and data post-processing. The data acquisition phase includes steps 302-310, and the data post-processing includes steps 312-316.

[0073] In the data acquisition phase, the method 300a includes selecting (302) a layout for sounding locations, setting up support frames and stand anchors for the exemplary instrument, calibrating the sensor and actuators of the exemplary instrument.

[0074] Method 300a includes advancing (304) the exemplary instrument vertically with constant pre-determined linear and rotational speeds. Method 300a includes continuously measuring (306) (i) the drill tip force and torque resistance, and (ii) optional sleeve friction and pore water pressure if additional sensors are added to the exemplary7instrument.

[0075] Method 300a includes monitoring (308) force and torque measurements and adjusting the exemplary instrument accordingly, which includes further substeps 308a - 308f. Specifically, method 300a includes determining (308a) if the maximum force of the exemplary7instrument is reached. If the maximum force of the exemplary7instrument is not reached, method 300a includes determining (308b) if there is a drop in force measurements (i.e., a stiff layer of soil has been passed through). If there is a drop in force measurements, method 300a includes resetting (308c) the rotational speed of the drill tip to its original value and continuing the advancement; otherwise, method 300a includes keeping (308d) the rotational and linear speeds of the drill tip as they are and continuing the advancement of the exemplary instrument.

[0076] If the maximum force is reached, method 300a includes determining (308e) if there is an increase in torque measurement. If there is an increase in torque measurement (i.e., stiffer layer of soil is reached), method 300a includes increasing (3081) the rotational speed of the drill tip to reduce reaction force, keeping the initially established linear speed, and continuing the advancement of the exemplary instrument; otherwise, as the exemplary instrument reaches a bedrock or a predetermined target depth, method 300a includes stopping (310) the advancement / penetration of the exemplary' instrument and entering the data postprocessing phase.

[0077] In the data post-processing phase, method 300a includes removing (312) noise in the collected measurement data and correcting sensor offsets using statistical methods.Method 300a includes characterizing (314) soil type using the (i) measured force and torque data, and (ii) optional sleeve friction and pore pressure data. Method 300a includes estimating the engineering properties of the subsurface materials (of the soil) using the measured force and torque data and the soil characterization.

[0078] In the example shown in Fig. 3B, the method 300b includes one phase: microtunneling, which includes steps 320 - 330.

[0079] The method 300b includes evaluating (320) subsurface conditions along a microtunnel alignment using penetration test, borehole, and laboratory test data for the soil depths of interest. Method 300b includes horizontally advancing (324) the exemplary instrument (i.e., as a micro-tunneling device in this method) at constant linear and rotational speeds of the drill tip to facilitate soil cutting with the drill tip and soil removal with the track belts. Method 300b includes continuously feeding (326) pipe segments at the back of the exemplary instrument as the exemplary instrument is progressing horizontally.

[0080] Method 300b includes monitoring (328) force and torque measurements and adjusting the instrument accordingly, which can include further substeps 328a - 328f. Specifically, method 300b includes determmmg (328a) if the maximum force-torque capacity of the exemplary instrument is reached. If the maximum force-torque capacity is reached (i.e., stiffer zone of soil is reached), method 300b includes reducing (328b) the linear speed and increasing the rotational speed of the drill tip to facilitate the advancement of the exemplary instrument.

[0081] If the maximum force-torque capacity is not reached, method 300b includes determining (328c) if there is a drop in force measurements (i.e., a stiff layer of soil has been passed through). If there is no drop in force measurements, method 300b includes keeping (328d) the linear and rotation speeds of the drill tip as they are and continuing the advancement of the exemplary instrument; otherwise, method 300b includes determining (328e) if the exemplary instrument reaches the target reception shaft. If the exemplary instrument has not reached the target reception shaft, method 300b includes reducing (328f) resetting the rotational speed of the drill tip back to the original value, and continuing the advancement of the exemplary instrument; otherwise, method 300b includes (330) stopping the advancement of the exemplary instrument.

[0082] Experimental Results and Additional Examples

[0083] A study was conducted to develop and evaluate a CPT-like instrument (also referred to as ‘"penetration test instrument’") comprising two actuators, a sensor, a drill tip, and a longitudinal shaft connecting the actuators, sensor, and drill tip together, as described inrelation to Figs. 1A - IB. The tip of the penetration test instrument can be used for microtunneling and other tunning / soil penetration operation.

[0084] Figs. 4A - 4B show (i) an experimental setup for evaluating, via X-ray scans and three-dimensional (3D) digital image correlation (DIC), the experimental instrument of the study and (ii) configurations (e.g., sizes, angles) for each of the components (e.g., sensor, actuators / stepper motors, motor driver, data acquisition logger, drill tip without a moving belt) in the instrument of the study.

[0085] Figs. 4C - 4D show 3D image of (i) a soil-based material / specimen (e.g., sand) and (ii) the drill tip penetrating the soil-based material / specimen in the study.

[0086] Fig. 4E shows the rotation speed (RS) and pitch-compatible speed (PCS) for four drill tips, in 12 scenarios, having different combinations of apex angles (e.g.. 30 and 60 degrees) and pitches (e.g., 20 and 30 mm / rev).

[0087] Fig. 4F shows X-ray images of the drill tip, of the instrument of the study, penetrating the soil-based material / specimen at different combinations of rotation speed (RS) and pitch-compatible speed (PCS).

[0088] Fig. 4G shows a continuum-based analysis, on the X-ray images in Fig. 4F. to assess the disturbance caused by the penetration of the drill tip into the soil-based material / specimen.

[0089] Fig. 4H shows reaction force measurements as a function of the ratio of rotation and axial speeds. As shown, the reaction force is higher when the rotation speed is lower, especially at a pitch of 30 mm / rev.

[0090] Fig. 41 shows torque measurements as a function of the ratio of rotation and axial speeds. As shown, the torque is higher when the rotation speed is higher, especially at a pitch of 30 mm / rev and an apex angle of 60 degrees.

[0091] Fig. 4J shows total energy measurements as a function of the ratio of rotation and axial speeds. As shown, with pitch-compatible speed, the drill tip penetrated the soil-based material with less energy .

[0092] Fig. 4K shows additional total energy measurements as a function of the ratio of rotation and axial speeds. As shown, with pitch-compatible speed, the drill tip penetrated the soil-based material with less cumulative energy, especially at a pitch of 30 mm / rev.

[0093] In Figs. 4A - 4K, the drill tip of the experimental system did not have a moving belt.

[0094] Fig. 5 shows another experimental setup and digital image correlation (DIC) analysis used to evaluate the track belt of another experimental instrument

[0095] Field Penetration Testing Operation. Besides evaluating the experimental instrument in the above-discussed laboratory setting, the study also employed the instrument in a field penetration testing operation. The study investigated a site with sandy silt at the surface using the experimental instrument in preparation for a wind turbine foundation.

[0096] The study selected a sounding location for the exemplary7instrument based on the desired location of the foundation. The study set up (i) the experimental instrument and its associated supports and stand anchors, and (ii) calibrated the sensors of the instrument for accurate measurements. The study deployed the experimental instrument and advanced the instrument linearly with concurrent rotation until a depth of 1.2 m. A sharp rise in both force and torque measurements was observed, indicating a stiff layer, and the rotation speed was increased to reduce the reaction force. As the penetration was continued, a drop in the torque measurements was observed, at which point the rotation speed was reduced to the initially set value. Advancement and rotation continued until a sudden spike in force measurements was observed without a proportional increase in the torque measurements, which indicated that bedrock was reached, at which point the instrument of the study was stopped. The forcetorque measurements were used to characterize the soil layering and classify the soil types. The soil layers were identified to consist of a loose sandy silt underlain by a dense sand layer, which in turn was underlain by a clay layer over the base bedrock.

[0097] Field Micro-Tunneling Operation. The study also employed the experimental instrument, as a micro-tunneling device / unit (see Fig. 6), in a field micro-tunneling operation to install a utility tunnel of 1 ,5m diameter at a depth of 6 m. The study investigated a site with loose silty sand in the upper Im, dense sand from 1 to 8m depth, and hard clay underneath based on penetration data and borehole logs along the tunnel alignment. The study predefined the linear and rotational speeds of the drill tip of the experimental instrument. The reception and launch shafts were prepared, and the thrust wall, jacking frame, and the instrument of the study were installed in the launch shaft. The instrument of the study was deployed from the launch shaft and was advanced horizontally towards the reception shaft which was 60 m away at a constant linear speed while the drill tip was simultaneously rotated. Pipe segments were continuously introduced through the launch shaft as the instrument of the study advanced. After 20m advancement, a sharp rise in both force and torque measurements was observed, indicating a stiff zone was encountered, and the linear advancement rate was decreased while the rotation speed was increased to reduce the reaction force. After the stiff zone was penetrated, the linear speed and rotational speed were reset to the original values until the instrument of the study reached the reception shaft 60m from the launch shaft. Oncethe instrument of the study reached the reception shaft, the advancement and rotation were stopped, as this is the end of the micro-tunneling operation.

[0098] Conclusion

[0099] As used in the specification and the appended claims, the singular forms "a." “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another implementation includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0100] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0101] Throughout the description and claims of this specification, the word “comprise” and variations of the w ord, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal implementation. “Such as” is not used in a restrictive sense but for explanatory purposes.

[0102] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application, including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific implementation or combination of implementations of the disclosed methods.

[0103] The following patents, applications, and publications, as listed below and throughout this document, are hereby incorporated by reference in their entirety herein.

Claims

What is claimed:

1. An instrument for a penetration test, the instrument comprising: a longitudinal shaft; a drill tip disposed at a first instrument end of the penetration test instrument and connected to the longitudinal shaft, wherein the drill tip is configured to axially and rotationally penetrate soil for soil analysis; a first actuator operatively coupled to the drill tip through the longitudinal shaft, wherein the first actuator is configured to move, in a linear motion, the drill tip from a first position in a first configuration to a second position in the soil; a second actuator operatively coupled to the drill tip and the first actuator, wherein the second actuator is configured to rotate the drill tip while the drill tip is being moved into the soil; and a force-torque sensor operatively coupled to the drill tip, wherein the sensor is configured to independently measure force and torque that the first and second actuators are required to apply to the drill tip while moving the rotating into the soil, and wherein the measured force and torque are outputted in a report to subsequently determine characteristics and properties of the soil.

2. The instrument of claim 1, comprising: a set of supports configured to mount and anchor the instrument for a given position for soil measurement.

3. The instrument of claim 1, wherein the drill tip, the first and second actuators, and the sensor are aligned with each other and arranged to be parallel to a longitudinal axis of the drill tip.

4. The instrument of claim 3, wherein the linear motion is parallel to the longitudinal axis of the drill tip.

5. The instrument of claim 1, wherein the drill tip has an apex angle varied between 30 and 60 degrees, and wherein the drill tip is attachable and reattachable for different soil types for a respective apex angle.

6. The instrument of claim 1 , wherein the drill tip has a pitch varied between one and 6 times the diameter ( ) of the drill tip, and wherein the drill tip is attachable and reattachable for different soil types for a respective pitch.

7. The instrument of claim 1, wherein the force-torque sensor is positioned on the longitudinal shaft.

8. The instrument of claim 1, wherein the force-torque sensor is integrated into the drill tip.

9. The instrument of claim 1, wherein the drill tip comprising: a longitudinal frame around a central shaft with a set of rollers attached to it; a set of rollers attached to the longitudinal frame; and one or more track belts, supported by the rollers, configured to revolve along a path aligned with the longitudinal frame.

10. The instrument of claim 9, wherein the drill tip and longitudinal frame have at least one shape of a square pyramid, cross-based pyramid, hexagonal pyramid, circular pyramid, and vortical pyramid.1 1 . The instrument of claim 9, wherein the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged to be parallel to a longitudinal axis of the frame.

12. The instrument of claim 9, wherein the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged in a helical manner with respect to a longitudinal axis of the frame.

13. The instrument of claim 1, wherein each of the first and second actuators is a stepper motor controlled by a motor driver.

14. An instrument for micro-tunneling, the instrument comprising: a longitudinal shaft;a drill tip disposed at a first instrument end and connected to the longitudinal shaft, wherein the drill tip is configured to axially and rotationally excavate soil; a first actuator operatively coupled to the drill tip through the longitudinal shaft, wherein the first actuator is configured to move, in a linear motion, the drill tip from a first position in a first configuration to a second position in the soil; a second actuator operatively coupled to the drill tip and the first actuator, wherein the second actuator is configured to rotate the drill tip while the drill tip is being moved into the soil; and a force-torque sensor operatively coupled to the drill tip, wherein the sensor is configured to independently measure force and torque that the first and second actuators are required to apply to the drill tip while moving the rotating to excavate the soil, and wherein the measured force and torque are outputted in a report to subsequently adjust motor controls and advancement rate.

15. The instrument of claim 14, comprising: a set of supports configured to mount and anchor the instrument for a given position for soil measurement.

16. The instrument of claim 14, wherein the drill tip, the first and second actuators, and the sensor are aligned with each other and arranged to be parallel to a longitudinal axis of the drill tip.

17. The instrument of claim 16, wherein the linear motion is parallel to the longitudinal axis of the drill tip.

18. The instrument of claim 14, wherein the drill tip has an apex angle varied between 30 and 60 degrees, and wherein the drill tip is attachable and reattachable for different soil ty pes for a respective apex angle.

19. The instrument of claim 14, wherein the drill tip has a pitch varied between one and 6 times the diameter ( / )) of the drill tip, and wherein the drill tip is attachable and reattachable for different soil types for a respective pitch.

20. The instrument of claim 14, wherein the force-torque sensor is positioned on the longitudinal shaft.

21. The instrument of claim 14, wherein the force-torque sensor is integrated into the drill tip.

22. The instrument of claim 14, wherein the drill tip comprising: a longitudinal frame around a central shaft with a set of rollers attached to it; a set of rollers attached to the longitudinal frame; and one or more track belts, supported by the rollers, configured to revolve along a path aligned with the longitudinal frame.

23. The instrument of claim 22, wherein the drill tip and longitudinal frame have at least one shape of a square pyramid, cross-based pyramid, hexagonal pyramid, circular pyramid, and vortical pyramid.

24. The instrument of claim 22, wherein the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged to be parallel to a longitudinal axis of the frame.

25. The instrument of claim 22, wherein the one or more track belts and a portion of the set of rollers are aligned with each other, and wherein the one or more track belts and the portion of the set of rollers are arranged in a helical manner with respect to a longitudinal axis of the frame.

26. The instrument of claim 14, wherein each of the first and second actuators is a stepper motor controlled by a motor driver.

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