Abstract: A conventional borehole shear tester is modified by incorporating a volume-monitoring accessory in the non-pressurized chamber vent line. This accessory includes a fluid reservoir operatively connected to the non-pressurized chamber of the shear head unit. A change in the level of fluid in the reservoir indicates changes in the volume of the non-pressurized chamber, which in turn indicates a change in shear head diameter. By maintaining a constant fluid level in the reservoir, the volume of the non-pressurized chamber remains constant and the shear head diameter remains constant. Thus, with the shear head diameter fixed, the normal pressure exerted on the wall of the borehole varies as the soil dilates or consolidates. Accordingly, the modified borehole shear tester of the present invention simulates friction pile behavior.

Abstract: An improved back-pressured pneumatic pressure cell is provided along with a method of using the same. The device includes at least one sensing cell mounted on a blade for insertion into the soil. The cell includes a perforated outer ring and a perforated central disk separated by a threshold. A resilient membrane covers the outer ring and central disk. A first back-pressure is applied through the perforations of the outer ring to the membrane, while a second back-pressure is applied through the perforations of the central disk to the membrane. The second pressure is slightly less than the first pressure. When the first pressure reaches the soil pressure, the seal between the membrane and the threshold is broken, thereby permitting a momentary reverse flow of pressure through the perforations of the central disk until the first and second pressures equalize, as monitored by a differential pressure gauge. A valve regulates the pressure differential between the first and second pressures.

Abstract: The soil testing device of the present invention includes a tapered body member having opposite tapered surfaces which converge toward one another at their lower ends. Within one of the tapered surfaces is a cavity having a diaphragm placed thereover. Beneath the diaphragm are a plurality of sensors which extend in a line between the upper and lower ends of the cavity. Means are provided for introducing fluid pressure into the cavity. When the device is inserted into the soil, the sensors sense the various pressures being exerted on the diaphragm by the soil, and record these pressures on a gauge or meter located above the surface of the soil.

Abstract: The device of the present invention comprises a frame having at least one sensor mounted thereon. The sensor includes a diaphragm flush with one surface of the frame, a porous filter flush with one surface of the frame, and a strain gauge bonded to diaphragm and in electrical communication with a read-out instrument. A passageway in the frame provides communication between the filter and the diaphragm such that the water pressure of the saturated soil is transmitted through the filter such that the soil pore pressure is exerted on the back side of the diaphragm. Simultaneously, the total pressure of the saturated soil is exerted on the front side of the diaphragm when the device is embedded in the soil. The strain gauge measures the net pressure on the diaphragm which is equal to the soil effective stress, thus giving a direct measurement of such stress.

Abstract: A method for preventing or greatly reducing damage to building foundations resulting from the swelling of moisture-expansive clay beneath and about such foundations. The method includes the steps of first forming a trench about the foundation, the trench extending well below the basement or on-grade floor slab of that foundation, and then substantially filling the trench with an extrudable plastic mass of hydrated lime and water to help stabilize the moisture-expansive clay and to provide a yieldable buffer capable of being displaced upwardly to accommodate horizontal expansion of the clay beneath and about the foundation, thereby relieving lateral stresses and reducing upward forces against the floor slab.

Abstract: A support system for a railroad track is described specifically adapted for the improvement of railroad subgrade performance. A plurality of vertically disposed piles are positioned below the ties and the rails of the track so that loads imposed on the cross ties will be distributed into the subgrade by the piles. The piles are preferably comprised of cementitious material. Each of the piles is comprised of a cylindrical stem portion having a funnel-shaped head portion at the upper end thereof. In one form of the invention, the cross ties rest upon the upper end of the head portion of the piles. In another form of the invention, a ballast material is positioned between the cross ties and the upper ends of the piles.

Abstract: A method of insitu testing of soil compressibility comprises boring a hole in the soil to be tested, reconstituting the lateral stress environment in the soil adjacent the bottom of the borehole and then performing vertical compression tests directly on the undisturbed material at the bottom of the borehole. The testing apparatus of the invention includes a cylindrical container adapted to be pushed to the bottom of the borehole. An inflatable circumferential membrane around the exterior periphery of the container is inflated to reconstitute the lateral stress environment. The load may be applied to the base of the borehole by either a closed or inflatable fluid cell or directly by a flat or stepped load plate.In one embodiment of the invention, a thin-walled cylindrical tube penetrates the soil at the base of the borehole so as to laterally support the test soil for substantially one-dimensional vertical compression testing.

Abstract: A method of waterproofing subterranean walls which generally comprises peeling back the sod, making a perimeter trench around the wall, making a plurality of spaced apart vertical bore holes in the soil adjacent said wall, introducing a highly ionic inorganic salt solution into the bottom of said holes without contacting the side walls of said holes, and thereafter filling the bore holes and the trench with asphaltic emulsion, and finally placing the sod back over the trench.

Abstract: A portable testing device for directly measuring developed lateral pressure induced on a material by a vertical applied pressure while the lateral expansion is adjustable. The testing device comprises a thin-walled cylindrical sleeve-like receptacle which is capable of lateral expansion in response to a vertical applied force on the material contained in the receptacle. The sleeve is provided with a slit formed in the wall thereof which extends between the upper and lower ends thereof to define first and second side edge portions. Apparatus is provided for preventing and/or adjusting lateral movement of the first side edge portion as the vertical applied force is applied to the material contained in the receptacle. A pressure sensing cylinder is connected to the second side edge portion and has a fluid pressure gauge operatively connected thereto for sensing the developed lateral stress.

Abstract: Apparatus and process of determining stress underground, the apparatus having a central standard or shaft provided with a sensing head formed of equally circumferentially spaced, radially extending blades or vanes carried at the lower end portion of the shaft. Sensor elements or cells are carried within each blade, each sensor element having a pair of spaced, deformable, deflection diaphragms separated by a porous interior. The sensor head is inserted directly into the ground or lowered through a hollow auger to project into the ground, therefrom. In other embodiments, the sensor head is carried by a flexible actuator riding in a curved track of a housing. The head, which may be a single blade or a plurality of blades with embedded sensor cells, is recessed in the housing and is projected sidewise from the housing by manipulation of the actuator.

Abstract: An expansible shear head device within a pulling cradle is lowered into a bore hole; and the device is expanded hydraulically to exert a predetermined normal pressure on the side walls of the bore hole. The pressure plates of the device are ribbed for permitting interlocking with the rock. Vertical shear stress is exerted on the rock by pulling on the device. The shear head includes a body having a plurality of hinge points, and is laterally expansible. A laterally extendible plunger with a movable shear plate is mounted opposite to a similar shear plate which is secured to permit some deflection of the body about its hinge points from its normal parallel configuration as the shear force moves the body through the bore. The body is locked in its normal parallel configuration until the shear force is applied.

Abstract: A testing device for measuring a lateral pressure induced on a material by a vertical applied pressure, the testing device comprising in combination a material-holding receptacle which is capable of lateral expansion in response to a vertical applied force on a material contained in the receptacle, and a sensing means positioned on the receptacle to sense the amount of lateral expansion of the receptacle.