Abstract: A profile sensor and method for mapping the variability in soil compaction and soil characteristics with respect to depth. One embodiment of the apparatus includes a tine with a plurality of cutting elements supported by a plurality of independent load cells configured to measure the force exerted on the cutting elements as the tine is pulled through the soil of a field. Soil cutting forces through the soil profile are preferably measured to a depth of 63 cm in increments of 7.5 cm. The profile sensor showed that the cutting force is influenced by soil moisture content, depth of operation of the tine and vertical location of the cutting element.

Abstract: A pressure converter insusceptible to the error of hydraulic pressure introducing position or the interference of installation depth of water and producing a signal corresponding to the effective soil pressure accurately while realizing cost reduction. since filters(34,35) are provided in an air gap(10) defined by two rigid plates(13,14) Receiving the soil pressure, a hydraulic pressure is applied but sand pressure is not applied. A load gauge(41) insensitive to the hydraulic pressure detects only the effective soil pressure. Since a signal cable(51) can be passed through the air gap(10), a plurality of pressure converters(1,2) can be coupled efficiently and since the signal cable(51,52) can be inserted internally, a pressure distributed in the depth direction can also be measured accurately.

Abstract: A multi-functional sensor system for simultaneously monitoring various parameters such as the structural, chemical and environmental conditions associated with a medium to be monitored, e.g., bridges, high-rise buildings, pollution zones, is provided wherein the system includes at least a plurality of wireless multi-functional sensor platforms embedded in the medium in which an interrogation unit transmits power and receives responses. Each wireless multi-functional sensor platform includes multiple channels for accommodating a plurality of sensor types to simultaneously monitor the parameters associated with the medium. Thus, the wireless sensor platforms are formed to include those sensor types which are considered germane to the intended medium to be monitored.

Abstract: A method is provided for performing wedge analysis for assessing wedge occurrence and instability in underground openings, such as mines, caves, and the like. The method scales full-span wedge predictions, accounting for both occurrence and instability potential of possible wedge geometries. The method also generates predictions for wedge failure potential and support demand to result in more economical support design for wedges.

Abstract: An apparatus and methods for determining in situ pore fluid and soil properties at a particular subsurface location are disclosed. In one embodiment, the apparatus comprises a penetrating tip member configured to penetrate soil. The apparatus further comprises an attachment module coupled to the penetrating tip member. The attachment module includes at least one mandrel that includes a piezo sensor. An in situ measurement of pore pressure is obtained by the piezo sensor at a depth that corresponds to the location of the at least one mandrel on the attachment module.

Abstract: To predict residual settlement quantity and residual horizontal deformation quantity of ground where a liquefaction phenomenon has occurred due to earthquake. Soils in situ (stratum B to stratum D) are sampled from ground, and are made to be element test object stratums. A stratum whose characteristic is well-known, or the like may be substituted for a numerical model (stratum A). Next, setting of input conditions is performed, and vertical stress, horizontal stress and initial shear stress, which are equivalent to applied load that the ground at a depth of the point suffers, are worked on to each stratum. This recreates a stress status of soil before earthquake occurs. Then, shear displacement and the movement quantity of interstitial water by earthquake are given to the test piece, and the quantity of shear stress and pore water pressure, which have occurred, is obtained.

Abstract: The device comprises a corer (1, 4) fitted with a flexible diaphragm (2) on its inside face, means (10) for driving the corer into the soil (11), means for breaking up the soil leaving the top orifice of the corer, means for applying axial forces on the diaphragm (2) and on the top face of the soil sample (12) contained in the corer, and means for measuring stresses and deformations to which the sample (12) is subject. While a measurement is being performed, the corer is held stationary in the soil (11).

Abstract: An apparatus and method are provided for continuously measuring the soil strength on-the-fly and at different depths. The apparatus includes a downwardly extending probe having an impedance sensor mounted on a leading edge thereof so as to be impacted by the soil as the probe is moved in a horizontal direction therethrough. A reciprocating drive is also provided which is effective for simultaneously oscillating the probe in an up and down movement while it is passing horizontally through the soil. The mechanical impedance exerted upon the sensor is then measured as the probe is passed both horizontally and up and down through said soil, thereby providing a continuous depth-variable profile of the soil strength over a large area.

Abstract: The in-situ measurement of the shear modulus of a surface layer of soil (12) is performed by apparatus in which a contact foot (11) with a preselected downward bias force engages a defined area of a region of soil. A drive transducer (13) shakes the contact foot (11) vertically and sensing transducers (17, 18) determine the force applied to the foot (11) and the resulting movement of the foot (11) and generate respective first and second output signals. The in-phase movement responsive output signal is analyzed in relation to the force signal to obtain a measurement of a single parameter which is representative of the stiffness provided by the soil (12). The shear modulus as well as the void ratio of the soil can be calculated from the stiffness. The drive transducer (13) is energized by an a.c.

Abstract: This invention relates to a method and apparatus for surveying the geometry of tunnels comprising measuring the position of a tunnel surface relative to an absolute three-dimensional coordinate system, using at least one reflectorless distance sensor mounted for orientation in three dimensions and calculating a deviation from a predefined geometry for the surface and displaying said deviation in real time.

Abstract: Metering equipment for metering fluid flow through an injector valve, comprising metering means and locating means arranged to locate such a valve in fluid communication with the metering means. The metering means are upstream of the locating means.

Abstract: A plurality of sensing units are buried at suitable intervals in an area of ground or a snow accumulation section to be observed. Each of the sensing units includes a gyro-sensor for, when external force acts on it as a result of the displacement of the ground or the snow accumulation section, sensing impulsive acceleration from the magnitude and direction of the displacement and the inclination of the sensing unit itself, and a transmission section for transmitting the sense data by radio. A base station acquires the sense data transferred from the sensing units, processes the sense data for each measuring point in real time, determines the movement of the ground and/or the snow accumulation section, and judges a state of the ground and/or the snow accumulation section on the basis of the movement.

Abstract: A section is prepared from a specimen of porous media, e.g., Rock, typically including filling the pore spaces with a dyed epoxy resin. A color micrograph of the section is digitized and converted to an n-ary index image, for example a binary index image. Statistical functions are derived from the two-dimensional image and used to generate three-dimensional representations of the medium. Boundaries can be unconditional or conditioned to the two-dimensional n-ary index image. Desired physical property values are estimated by performing numerical simulations on the three-dimensional representations. For example, permeability is estimated by using a Lattice-Boltzmann flow simulation. Typically multiple equiprobable three-dimensional representations are generated for each n-ary index image, and the multiple estimated physical property values are averaged to provide result.

Abstract: The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

Abstract: A single open ended testing cylinder which is attached to wireline probe instrumented head is positioned at the lower end of a conventional hollow-stem drilling auger which is penetrated into the soil therebelow. During testing cylinder is rotated in the soil while torsional loading is measured and axial loading bypassed.

Abstract: A lateral motion sensing assembly for sensing movement experienced by a structural member such as a support beam or driven pile. The sensing assembly is immersed within a casing which is mounted to the structural member. The sensing assembly includes a support body and an accelerometer mounted to the support body for measuring movement of the structural member. The accelerometer is aligned with an anticipated line of motion such that measurements can be made along this line of motion. A pair of lever arms are pivotally mounted to the support body for removably securing the support body within the casing. A spring is mounted between the support body and lever arms for continuously biasing the lever arms to a position perpendicular with the support body.

Abstract: A multi-depth deflectometer provides use and fabrication advantages. It is comprised of a head member that normally is disposed at the very mouth of a bore hole, an elongated tail member extending down through the bore hole. Displacement transducers are removably positioned within the head member which can be opened from the surface. The transducers can be easily placed in or removed by hand. The first trackings of subsurface deflections are done through mechanical deflection anchors located at desired measuring levels within the tail member. The deflection anchors have transverse-bite actuators and are each separately in vertical-actuation communication with one of the transducers. A method of implementing the MDD reflects the use and fabrication advantages also.

Abstract: Sounding apparatus for pressing a sounding rod into a piece of ground in order to determine the soil properties at various depths, comprising a sounding rod which is intended to be pressed into a piece of ground; first and second clamping members for alternately clamping the sounding rod in place; first drive means for moving the first clamping member up and down in the longitudinal direction of the sounding rod; in which apparatus the first and second clamping members can be separately actuated between an open position and a closed position; second drive means are provided for moving the second clamping member up and down in the longitudinal direction of the sounding rod; and control means are provided, which are connected to the clamping members and drive means for alternately clamping in place, releasing and moving the respective clamping members up and down.

Abstract: Methods for augmenting the load bearing characteristics of short aggregate piers include preloading matrix soils, adding chemical additives to matrix soils and using mesh reinforcement in matrix soils and in cooperation with the aggregate lifts associated with pier constructions. Methods for expanding the feasibility of short aggregate piers include the use of gradations of aggregate, reducing friction between the short aggregate pier and adjacent matrix soils using liners or lubricating materials, controlling liquefaction by employing aggregate drains in short aggregate pier constructions, the use of non-impact forces alone or in conjunction with vibratory forces in construction short aggregate pier lifts, and the use of indigenous materials in short aggregate pier constructions.

Abstract: A method for determining unknown stress parameters in earth formation measures velocities in four sonic transmissions modes (compression, fast shear, slow shear and Stoneley) at a series of depths. Relationships between measured velocities and other measured values, two independent linear constants, and three nonlinear constants associated with equations of motion for pre-stressed isotropic materials are expressed in a set of four or five velocity difference equations derived from non-linear continuum mechanics. The velocity difference equations are solved using inversion for useful stress parameters, including maximum horizontal stress, minimum horizontal stress, pore pressure, and change in pore pressure over time.

Abstract: A method for evaluating the compaction, by means of a vibrator compaction device having mass Mvib and a bearing area F, of a preselected soil layer, for which a predetermined degree of compaction is desired, at a preselected depth l in a soil base having at least one layer disposed between an exterior upper surface and a hard bottom layer, thereby defining a vibrator-soil-base system, which includes the steps of: evaluating a desired volumetric mass &ggr;st of the preselected soil layer corresponding to the desired degree of compaction, which may be performed by measurement or by calculation using standard soil data; calculating a mass per unit area msoil of the preselected soil layer as a function of the desired volumetric mass; calculating the effective vibrating mass M of the vibrator-soil-base system as a function of the mass per unit area of the preselected soil layer and the mass of the vibrator; determining the natural oscillation frequency &ohgr;o of the vibrator-soil-base system when the preselected

Abstract: A method is provided for determining an in-situ stress of an earth formation subjected to first, second and a third in-situ stresses, wherein a borehole has been drilled into the formation, the borehole containing a borehole fluid inducing a selected pressure to the borehole wall so that in a region of the formation the first in-situ stress is replaced by another stress depending on the selected pressure induced to the borehole wall.

Abstract: The invention is a method to operate a heat injection well, the method comprising the steps of: providing a heat injection well comprising a metal casing and a controllable source of heat within the casing; determining the maximum temperature of the casing which can be applied to the metal casing as a function of external pressure; providing a formation stress measurement device within the formation in the vicinity of the wellbore; providing a temperature measurement device effective for determining the temperature of the casing; determining the formation stress during operation of the heat injection well; and controlling heat released from the controllable source of heat to maintain the formation stress below a predetermined fraction of the collapse stress of the casing.

Abstract: A self-orienting motion sensor in which an inner housing, preferably spherical, is free to rotate within a cavity, also preferably spherical, resting on a support in an outer housing. The inner housing has a preferred orientation due to the center of gravity being lower than the rotational center of the inner housing. Motion sensing elements are arranged within the inner housing to measure at least one and preferably three directions of motion. A signal transfer mechanism transfers signals to a recorder. The inner housing may include a magnet to orient it in a defined relation to the earth's magnetic field and the housing may be provided with ground engaging devices to fix the housing in the ground.

Abstract: A novel method and apparatus for measuring the dynamic loading characteristics of a soil bed is provided. The invention pertains to a method and apparatus for measuring, as a function of time, the resistance to penetration offered by a soil bed as the apparatus is fed into the soil at a constant rate. The device of the invention measures and records the multidirectional forces exerted upon it as it is fed through varying layers and types of soil in order to determine the types of soil encountered, their resistance to leading forces, and their various thicknesses and compositions. The device and method are particularly useful for testing and evaluating the bed surfaces of railroads and highways.

Abstract: A downhole tool facilitates in-situ borehole measurement of stress required to initiate a fracture in a desired direction in subterrean formation. The tool is constructed by longitudinally splitting a cylinder in half, and in use the tool includes an inflatable packer disposed within the split cylinder to force each half of the split cylinder against the borehole wall when the packer is inflated. Each half of the split cylinder, which serves as a borehole platen, is made to better conform to an irregular surface of a borehole wall by dividing the split cylinder into multiple segments that are loosely joined so as to allow limited independent movement of each segment with respect to adjacent segments.

Abstract: An apparatus for securing a soil testing device and other attachments necessary for soil testing near the bottom of a borehole uses a pair of clamps with gripping teeth that interlock with similar gripping teeth in the internal wall of the auger. The lateral movements of the clamps toward the auger are controlled so that the soil testing device is maintained in a proper orientation with respect to the soil sample and to avoid uncontrolled engagements of the clamps with the auger.

Abstract: A stress measuring rock support device is provided, such as a cable bolt or friction stabilizer, which has an internal longitudinal cavity, such as a groove or a flat section on the kingwire or a hollow core in the kingwire or the like. One or more rigid wires or filaments extend in such cavity and their ends are anchored at predetermined anchor points within the cavity. The other ends of the rigid wires or filaments are spring-loaded and are provided with movable actuators having electrical contacts which are in contact with a linear potentiometer and measure the displacement of the actuators resulting from the stretch of the cable. This is then correlated to measure the cable load or strain resulting from the stress applied to the rock support device. The spring-loaded arrangement as well as the linear potentiometer and the actuators with electrical contacts are enclosed within a suitable cover to form an instrumentation head assembly for the rock support device.

Abstract: A core sample test apparatus applies pressure to the core sample and measures responsive longitudinal deformation with two sensors and lateral deformation with two orthogonal pairs of diametrically disposed sensors. The apparatus holds the core sample under test in a sleeve to which no or insignificant end torsional forces are applied during installation due to rotationally blocked washers used adjacent the ends of the sleeve. Concurrent acoustic testing can also be applied.

Abstract: A self-orienting motion sensor in which an inner housing, preferably spherical, is free to rotate within a cavity, also preferably spherical, resting on a support in an outer housing. The inner housing has a preferred orientation due to the center of gravity being lower than the rotational center of the inner housing. Motion sensing elements are arranged within the inner housing to measure at least one and preferably three directions of motion. A signal transfer mechanism transfers signals to a recorder. The motion of the inner housing may be limited in a pre-determined range, the inner housing may include a magnet to orient it in a defined relation to the earth's magnetic field and the housing may be provided with ground engaging devices to fix the housing in the ground.

Abstract: An improved technique to more accurately calculate pore pressure of sedimentary rock due to subsurface fluid expansion where the technique is built upon a combination of known force balanced in situ loading limb mineralogical stress/strain relationships with locally variable unloading stress/strain relationships, including that in stress/strain space, the material properties governed loading limb is an upper limit for the many possible unloading limbs; also, a method for relating these different natural stress/strain paths and applying the correct path to calculate pore fluid pressure from in situ force balance is disclosed such that the method is preferably calibrated with in situ stress/strain data which allows for a lithologic sealing caprock to be identified and the locally prevailing in situ unloading limb stress/strain relationship to be estimated, where the forced balanced loading and unloading calibrations are applied to more accurately determine well casing depths using either wireline or real-time "

Abstract: A system and method for providing analysis and evaluation of penetration test data for modifying Becker Hammer drill programs while in progress by measuring the bounce chamber pressure of a diesel hammer. The system comprises a pressure transducer connected to the bounce chamber for sensing the bounce chamber pressure, a data logger for monitoring the pressure transducer, storage means, a control module and a keyboard having a display screen to enable user control of the data logger, a telephone modem, and a series of instructions for controlling the schedule, pressure transducer measurement, control module signal monitoring, computation of data, and data storage operations of the data logger.

Abstract: A device for detecting deformations in solids includes a casing constructed and arranged to be insertable in a solid. The casing has walls defining a substantially closed container. The container has an inner dividing wall separating the container into an upper enclosed section and a lower enclosed section. A fluid substantially fills the lower enclosed section and is in fluid communication with the interior walls of the lower enclosed section. A first strain-sensing system is in fluid communication with the lower enclosed section of the container such that deformation of the walls causing pressure changes in the fluid are detected by the first strain-sensing system. A second strain-sensing system is disposed in the upper enclosed section. The upper enclosed section is at least partially filled with fluid. A valve fluidly couples the second strain-sensing system to the lower enclosed section.

Abstract: An apparatus and method for detecting the location of subsurface markers in a formation proximate to a borehole. The apparatus includes marker detectors in a housing having at least two housing sections attached in an initial orientation. The distance between the detectors is measured under controlled conditions with a calibration bar. The initial attached orientation between the housing sections is identified with a calibrator, and deviations from the initial attached orientation are identified by the calibrator after the housing sections are detached and reattached. The calibrator permits well site corrections to be made to the housing sections without recalibration. Gauges permit corrections for temperature and pressure fluctuations, and the corrected distances between the housing detectors is computed.

Abstract: An apparatus for measuring in situ stresses surrounding an active earthquake fault and forecasting shallow earthquakes includes a network of monitoring stations, each operating a respective borehole assembly for measuring in situ lateral stresses. The monitoring stations are arrayed along a recognized fault plane and arranged to straddle the fault plane, so that lateral stress readings may be obtained throughout the ground media surrounding the fault zone. All of the monitoring stations communicate with a central data-gathering facility, so that real-time analysis of changes in lateral stress orientation and magnitude surrounding the fault zone may be undertaken, and the results used to forecast forthcoming seismic events. Each borehole probe assembly includes a trio of single fracture expansion probes operated periodically, reiteratively, and automatically to expand against the borehole wall and determine the principal maximum and minimum lateral stress vectors in the underground media.

Abstract: Apparatus for determining compressive stress in an in-situ roof support pillar may comprise a convergence meter positioned in one of the two entries for measuring the total entry convergence, i.e., roof sag and floor heave, and for generating an output signal related thereto. A computer system connected to the convergence meter is responsive to the output signal and calculates the compressive stress in the pillar based on the total entry convergence and based on whether the pillar is being subjected to at least one of a number of load types including a first front abutment load, a second front abutment load, and a side abutment load.

Abstract: Apparatus comprises a probe for measuring snow pack movement, comprising a mobile element adapted to contact and be displaced by the snow pack, a static element linked to the mobile element by linkage means and adapted to remain stationary relative to the ground, and measuring means to measure relative movement of the two elements. The mobile element comprises a wand (16; 166) adapted to be placed in contact with a snowpack and having tilt means (20(a); 20(b); 168) that permit the wand to tilt away from the vertical in response to lateral movement of the surrounding snow pack. The measuring means comprises a movement sensor (50; 170) connected to the wand that measures the resulting movement of the wand. Data relay means transmits electronic signals generated by the movement sensor to a remote data collection and storage means.

Abstract: An extensometer for use in a borehole comprises a combination of linear motion transducers located with daisy wheel anchors, which may be attached together if desired with extension bars. Linkages are used to connect the transducers to the daisy wheel anchors. The transducers are set up to measure distance changes both axially along the hole or radially. The extensometer includes at least one axially measuring transducer, and at least two radially measuring transducers. The transducers change in value according to changes in borehole dimensions; the transducer values are monitored electrically.

Abstract: A device for measuring soil pore-air pressure in a high shock environment characterized by a shock resistant housing containing a plurality of pressure sensing ports with sintered metal filters mounted therein which filter fine soil particles, withstand high pressure shock, and permit high air flow. When the device is installed in the ground and an explosive is detonated nearby, soil particles are filtered from the air blast by the sintered metal filters, thereby enabling the device to provide accurate pore-air pressure measurements.

Abstract: A recoverable, multiple position borehole strainmeter is provided. The strainmeter includes at least two anchors having pistons for releasably engaging the borehole whereby to mount the strainmeter in the borehole. A pneumatic actuator for controllably, independently actuating the pistons to engage the borehole is provided. A biasing mechanism prevents the pistons from engaging the borehole when the pistons are not being actuated by the actuator, and a relative displacement sensor senses changes in relative displacement between adjacent anchors whereby to monitor relative mass displacement axially along the borehole between the anchors.

Abstract: A method and apparatus for testing the load-bearing capacity of a subterranean formation surrounding a concrete shaft and is made up of an expansion chamber at the bottom of the hole containing the shaft and fluid pressure and return lines which extend downwardly into communication with spaced outer peripheral portions of the expansion chamber so that when fluid is pumped into the chamber any entrapped air can be removed through the return line, and when grout is subsequently pumped into the chamber any fluid can be displaced through the return line. Telltale measuring rods extend downwardly into contact with spaced outer peripheral portions of the expansion chamber to measure displacement of the chamber when pressurized fluid is delivered into the chamber. The method of testing may be applied also in cyclical loading of the formation beneath the shaft to simulate a support structure which undergoes large fluctuations in loading, for example, of the type induced by an earthquake.

Abstract: In a longwall mining operation, a panel to be extracted is formed in a seam of mine material by longitudinally extending headgate and tailgate entries with the panel beginning in a set-up room and ending at a termination line in a recovery room. The recovery room is developed in two stages and is supported by primary and secondary roof support systems that include mechanical roof bolt assemblies, roof trusses, and channel members. The effectiveness of the roof support systems to support the overlying rock strata and withstand the abutment pressure exerted on the strata by the advancing longwall face as it approaches the recovery room is monitored by an instrumentation plan. Data gathered from the instruments is continually monitored as the longwall panel recovery operation progresses.

Abstract: A device positionable in a borehole for determining rock mass deformability, comprises a generally cylindrical body having at least one pair of diametrically opposed, elongated expandable wall portions for pressure contact engagement with the borehole wall, the wall portions being radially outwardly expandable in diametrically opposite directions along a predetermined axis extending transversely to the longitudinal axis of the borehole. An elongated core is arranged in the body and extends longitudinally thereof. A chamber is associated with a respective one of the expandable wall portions and is defined between the respective expandable wall portion and the core, the chambers associated with the at least one pair of expandable wall portions being in fluid communication for receiving a fluid under pressure.

Abstract: Process for packaging a sensor (1) to be placed in a road (2), characterized in that it consists in covering said sensor (1) with threads (8) of organic or inorganic material extending over the entire length of sensor (1) and in burying the whole in a binder that hardens by polymerization, so as to obtain a bar (7) containing said sensor (1).

Abstract: A modular sonde may be configured in various ways for measurements in open or cased boreholes. The sonde is conveyed on an electric wireline with or without a coiled tubing for conveying hydraulic energy from the surface. Modules common to the configurations include telemetry electronics, orientation, hydraulic energy accumulator, fluid chambers, hydraulic power, pumpout, and flow control. Each configuration has a stress/rheology module suited to the borehole situation. An open-hole sonde configuration has a stress/rheology module with an instrumented, inflatable packer module, an orienting module, and a probe module. A second open-hole sonde configuration has a stress/rheology module with an instrumented straddle-packer assembly. A cased-hole sonde configuration has a gunblock assembly, a gunblock orienting module hydraulics for formation pretest and hydraulics for stressing the formation to obtain data related to formation stress characteristics.

Abstract: A three-dimensional displacement measuring system measures the three-dimensional displacement of a mass such as rock. A first cylindrical member is provided as a displacement indicating device and is arranged on one side of a discontinuous surface, such as a crack, in a bore hole in the rock. The bore hole extends across the discontinuous surface. A second cylindrical member is provided as a displacement measuring device on the other side of the discontinuous surface and is free to displace relative to the mass and the first cylindrical member and is located opposite to the first cylindrical member.

Abstract: An inference device for discriminating an earthquake includes an ON/OFF signal generating means for generating an ON/OFF signal corresponding to an oscillatory wave, a characteristic parameter extracting means for extracting at least one of three characteristic parameters consisting of an ON period, an ON time sum total and a maximum ON time value based on the generated ON/OFF signal, and an inference means for inferring for each ON period based on the extracted characteristic parameter whether or not an earthquake happens.

Abstract: The invention relates to the field of measuring instruments and, in particular to sensing apparatus capable of measuring displacement or deformation for the ultimate purpose of monitoring strain and/or stress. The vibrating wire measuring principle provides a very reliable method of measuring small deformations with high precision. Measurement apparatus utilizing this principle, however, tend to be limited in range to the elastic limit of the stretched wire. To increase the useful range of measurement of a vibrating wire monitor, a spring may be placed in series with the wire. In order to prevent the spring from vibrating during the resonancing of the wire and thereby delaying the determination of the wire's resonant frequency, the invention contemplates isolation of the spring from the wire in a vibrational sense. In one form of the invention, isolation is achieved by causing a nodal point to be formed on the spring side of the wire. The nodal point may be formed by pressing a fret against the wire.

Abstract: A method and apparatus for detecting pipe penetration by the bore head of horizontal boring machine utilizes acoustic and seismic sensors. A sensitive acoustic microphone is placed in the bottom of the nearest sewer manhole to the location of the bore head to detect acoustic signals transmitted through the ground by the bore head for producing a first output signal. A seismic pickup device is placed in the vicinity of the bore head to detect vibrations of the ground caused by the bore head, as it moves through the ground, to produce a second output signal. These first and second signals produced, respectively, by the microphone and the seismic pick-up device, then are supplied to a two-channel strip chart recorder, which provides an output indicia permitting simultaneous comparison of the two signals. Particular patterns of these detected signals are indicative of the penetration of a sewer pipe.

Abstract: Methods and apparatus for determining whether soil is satisfactorily compacted. An operator delivers impact energy to the soil, and the amount of impact energy transmitted through the soil is repeatedly sensed and stored. A modelling formula, which approximates the variation of the stored amounts of impact energy, is used to generate current and target values for the level of compaction; if the current value equals or exceeds the target value, the soil is considered to be satisfactorily compacted.