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<br />When horizontal layer widths do not provide adequate working widths, the stair-step layers <br />can be sloped on a grade of 1 V:8H or flatter toward the water line. Sloping the individual <br />layers will provide a greater working surface without increasing the quantity of soil cement. <br /> <br />2. Facing Dimensions for Slope <br />Protection using Plating <br />Method <br /> <br />On smaller slope protection <br />projects a single layer of soil <br />cement can be placed parallel to <br />the embankment. In this technique, <br />known as plating, a single lift of soil <br />cement is applied on slopes of <br />1 V:3H or flatter (see Figure 2.4). <br /> <br /> <br />All extremities of the soil cement <br />facing should be tied into <br />nonerodible sections or abutments <br />to prevent undermining of the rigid <br />layer. Some common methods used to prevent undermining are placing a riprap apron at <br />the toe of the facing, extending the installation below the anticipated scour depth or <br />providing a cutoff wall below the anticipated scour depth. <br /> <br />Figure 2.4 Soil Cement placed in the plating <br />method parallel to the slope (PCA) <br /> <br />As with any rigid revetment, hydrostatic pressure caused by moisture trapped in the <br />embankment behind the soil cement facing is an important consideration. Designing the <br />embankment so that its least permeable zone is immediately adjacent to the soil cement <br />facing will reduce the amount of water allowed to seep into the embankment. Also, <br />providing free drainage with weep holes behind and through the soil cement will reduce <br />pressures which cause hydrostatic uplift. <br /> <br />3. Grade Control Structures <br />Grade control structures (drop <br />structures) are commonly used <br />in Arizona to mitigate channel <br />bed degradation (see Figure <br />2.5). The location and spacing <br />of grade control structures <br />should be based on analysis of <br />the vertical stability of the <br />system. Toe-down depths for <br />soil cement bank protection <br />below drop structures should <br />be deepened to account for <br />the increased scour. Some <br />typical sections of soil cement <br />grade control structures are <br />shown in Figure 2.6. <br /> <br /> <br />Figure 2.5 Soli cement bank protection and drop <br />structures In laughlin, NV (Hansen) <br /> <br />2.5 <br />