BOTT TIMOTHY ALLEN (US)
GRAVIER ROBERT ALLAN (US)
BOTT TIMOTHY ALLEN (US)
US5419092A | 1995-05-30 | |||
US5177925A | 1993-01-12 | |||
AU636100B3 | 1993-04-08 | |||
US5564865A | 1996-10-15 |
3 Figure 3 is a schematic view showing three blocks arranged in two courses; Figure 4 is a perspective view similar to Figure 3 but showing placement of a rod and flexible anchor sheet; and Figure 5 is a diagrammatic view showing a retaining wall in place against an earthen embankment; Description of Preferred Embodiments Figures 1 and 2 show a plantable block 10 suitable for use in forming a plantable retaining wall, the block having an upright front wall 12, laterally spaced side walls 14, 16, a rear wall 18, and a bottom wall 20. The front wall has an upwardly extending lip 12.1 that extends upon the elevation of the side and rear walls. The bottom surface 22 of the blocks (Figure 3) may be planar, and the bottom wall may have an aperture formed in it (not shown) to aid in drainage. As shown best in Figure 2, the block 10 has an upwardly open interior 24, and the intersections of the interior walls are rounded to avoid stress concentrations and to aid in the ease of manufacturing the block through the pouring of concrete into a mold. The rear wall 18 desirably has a thickness "t" (Figure 2) that is greater than the thickness of the side walls 14, 16 for reasons that will become evident from the description that follows. The upper surface 18.1 of the rear wall 18 has a generally centrally positioned opening 18.2 formed in it, the opening extending downwardly at least to the level of the upper surface 20.1 of the bottom wall 20, so that when the block is employed in a retaining wall, water within the interior 24 of the block may drain rearwardly out of the block. If desired, the upper surface 20.1 of the bottom wall may be slanted downward and rearward to aid in drainage. As shown best in Figures 1 and 2, the side walls 14, 16 have grooves 14.1 , 16.1 formed in them, the grooves extending downward from their upper surfaces and extending through the thicknesses of the side walls. The grooves are aligned with each other, and are spaced, desirably, at equal distances from the front wall 12. In the embodiment of Figures 1 , 2 and 3, the grooves are formed such that the rear portion of each groove coincides with the forwardly facing wall 18.3 of the rear wall 18, but if desired, the grooves 14.1 , 16.1 may be moved forwardly US2005/021718
slightly to provide a short length of side wall between the grooves and the forwardly facing surface of the rear wall. As explained in greater detail below, the grooves are configured to receive within them a rod. As depicted, the grooves have a rounded bottom 14.2, 16.2 so as to closely receive a rod that has a generally circular cross section. The rod may have any appropriate cross section, such as a square cross section, and the bottom surface 14.2, 16.2 of the grooves may be similarly shaped if desired. Upper surfaces 14.3, 16.3 of the side walls are generally substantially co-planar with the upper surfaces 18.1 of the rear walls, although the upper surfaces of the rear walls may be depressed slightly to accommodate a flexible anchor sheet, as described below. Figure 3 depicts schematically how two adjacent courses of blocks may rest one upon the other. In Figure 3, the bottom surface 22 of the upper block 10.1 rests upon the upper surfaces 14.3, 16.3 of the side walls and the upper surface 18.1 of the rear wall of the blocks 10.2 in the lower course. The front surface 12.2 of the upper block 10.1 is positioned slightly to the rear of the front surfaces 12.2 of the lower course of blocks 10.2, so that the bottom front edge 12.3 of the top block is received in the intersection 12.4 between the lip 12.1 and the side walls 14, 16, as shown in Figure 2. The slope of the resulting wall may thus be controlled by the front-to-rear thickness of the lip 12.1. The blocks of the invention can be made through a process similar to that taught in Gravier, U.S. patent 5,484,236, the disclosure of which is incorporated herein by reference. An upwardly open mold box having walls defining the exterior surfaces of the front, side and rear walls of a block is positioned on a conveyor belt, the rear wall portion including an insert matching the rear opening 18.2 of the block. A removable top mold portion is configured to match the surfaces forming the upwardly open interior 24 of the block and also the inner portion of the upper lip 12.1. A zero slump concrete slurry is poured into the mold and the top mold portion is inserted, care being taken to distribute the slurry throughout the interior of the mold, following which the top mold portion is removed, as are the front, rear and side walls of the mold box, and the block is allowed to fully cure. US2005/021718
5 Referring now to Figure 4, which is similar to Figure 3 but which shows added features, an elongated rod 26 is received within the grooves 14.1, 16.1 of at least two adjacent blocks 10.2 of a lower course of blocks. The rod itself may be circular in cross section, or may have various other cross sections as desired, and the rod desirably is hollow, that is, tubular. It is contemplated that the rod, in the form of tubing having small perforations through its wall, may be employed to deliver water to plants growing in the upwardly open spaces of the wall. Note should be made that the rod 26 extends laterally through the grooves of at least two adjacent blocks 10.2 in the lower course, the rod in this manner, serving to maintain lateral alignment and also forward/rearward alignment between adjacent blocks in the course. The rod 26 itself may be made out of a flexible material such as polyvinyl chloride tubing or the like, the rod desirably having sufficient flexibility to enable the blocks in a course to laterally conform smoothly to a curved embankment. That is, the rod may be sufficiently rigid to maintain alignment between adjacent blocks in a course, but may bend on a large radius to enable the blocks in the course to conform smoothly to the contour of an embankment. As shown in Figure 4, an anchor sheet 28 is provided. The lateral width of the anchor sheet is greater than the width of two adjacent blocks. The forward end portion 28.1 of the sheet is attached to the rod 26, and may, as shown in Figure 4, be wrapped around the rod with the end 28.2 of the sheet being brought back rearwardly for a distance of a foot or so. In this manner, the sheet (and in this example, two thicknesses of the sheet), pass over the upper surfaces 18.1 of the rear wall of the lower course 10.2 of blocks. The bottom surface of the upper course of blocks 10.1 bears downwardly upon the upper side wall surfaces 14.3, 16.3 of the bottom blocks, and presses downwardly upon the anchor sheet as the anchor sheet passes over the upper surfaces 18.1 of the rear wall, pinching the anchor sheet between these surfaces. In this manner, the rod 26 is locked in its position within the grooves by the bottom surface of the upper course of blocks, and the anchor sheet is firmly attached to the rod. The resulting connection between the anchor sheet and the blocks is such that when a rearward tensile force is applied to the anchor sheet during a testing operation, neither the concrete block structure nor the attachment of the anchor sheet to the rod fails 18
6 before the anchor sheet itself begins to yield. As mentioned above, the rear wall has a thickness "t" that is greater than the thickness of the side walls, the thick rear wall providing a wide surface across which the rod ands wrapped anchor sheet may bear rearwardly, and also adding strength to the block so that the rear wall of the block is not broken off rearwardly in response to a high rearward- directed tensile force on the anchor sheet. The anchor sheet can be any of several materials that are resistant to degradation in moist soils. The sheet desirably is perforated so as to enable rainwater to flow downwardly through the openings in the sheet and not become trapped by the sheet. Materials known as geogrid materials can be appropriately used, these materials being formed, for example, of high density polyethylene or high tenacity polyester. They may be in the form of net-shaped synthetic polymer- coated fibers. Geogrid sheets are available commercially; one such material being sold under the trademark FORTRAC, by Huesker Inc. A retaining wall 30 is shown schematically in Figure 5, and comprises blocks 10 that are supported upon one another in the manner described above in connection with Figures 3 and 4. In the drawing, every second course of blocks is provided with a rod 26 and an anchoring sheet 28. If desired, each course of blocks may be provided with a rod and anchoring sheet, or every third or fourth course may be so provided, depending on such factors as the geometry of the system and the type and nature of the local soils. A soil embankment is shown at 30.1, and in Figure 5, a portion of the backfilled soil has been left clear of cross hatching to show structure and position of the anchoring sheets. Perforated drain tiles 32 may be positioned as shown and are vented to the exterior of the embankment. Desirably, drain rock 34 is positioned beneath the first course of blocks. As exemplified in Figure 5, a base comprising a six inch deep layer of drain rock is provided that is level and compacted in a twelve inch deep trench so that the top of the drain rock is below grade. The embankment 30.1 is first excavated, and the retaining wall is constructed course by course, with back fill of earth occurring periodically and at least after each course of blocks carrying a rod and anchor sheet are laid. As will be evident, the anchoring sheets 28 are placed for the purpose of restraining the blocks 10 from moving forward, away from the embankment. The use of anchor sheets, and the formation, course by course, of retaining walls of this type are known, and need not be described further. As desired, if the rod 28 is a perforated plastic pipe, such as polyvinyl chloride, the pipe may be connected to a source of water so that plants in the wall may be periodically watered. The use of an elongated rod that extends through grooves in a plurality of blocks in a course contributes to the ease with which the blocks may be placed and positioned, the rod serving to maintain lateral alignment between adjacent blocks in a course, and flexibility of the rod contributing to the formation of a smooth curve to match the planned smooth curve of the embankment. The anchor sheet, which extends laterally along a plurality of blocks, tends to distribute any tensile loads experienced by the sheet and thus reduces the likelihood that the sheet will rupture under localized high tensile loads. While preferred embodiments of the present invention have been described, those skilled in the art will recognize that further modifications may be made without departing from the intent of the invention. All such modifications are intended to be claimed as that fall within the scope of the invention.
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