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<br />. ~ <br /> <br />000715 <br /> <br />-2- <br /> <br />II. DURING SOIL MASS MOVEMENT <br /> <br />8. There is essentially a very small window of soil mass flow rates during <br />which human effort can effectively mitigate the potential damming of a <br />river. There are basically four possible stages of a slide. They are: <br /> <br />1. The sl ide does not move. No effort required. <br /> <br />J 3.)1 I 2. <br /> <br />3. <br /> <br />The slide moves very slowly. The river erosive forces will keep the <br />river channel open. Human effort not needed, but could be helpful. <br /> <br />The slide moves too fast and the river cannot keep the channel open. <br />With the aid of men and machinery, such as draglines, scrapers, <br />bulldozers, trucks, etc, it is possible that the channel can be kept <br />open. However, this possibility is a function of the soil mass flow <br />rate being less than the machine and water flow excavation rate. <br /> <br />I_ <br />.' <br /> <br />4. The slide moves faster than the river, human effort and machinery <br />could handle. A dam is being formed. <br /> <br />If a dam is being formed, there are still a few actions that could be <br />attempted to mitigate potential problems. <br /> <br />'A. <br /> <br />Install a pipe to handle part or all of the flow. Armco (phone <br />455-4080), Thompson Pipe & Steel Company (phone 292-4080) and other <br />companies usually carry a large stock of several hundred or thousand feet <br />of 24 inch, 30 inch, 36 inch, 42 inch, and 48 inch pipe and possibly 60 <br />inch pipe. If the resources are combined, one or more lines could be <br />placed. (See figures 1 through 6 for pipe discharge capacities) <br /> <br />" <br /> <br />}. " <br /> <br />Additional drain pipes could be installed at a <br />anticipation of the slide continuing to move. <br />opposite side of the moving soil mass, a ledge <br />pipeline installed. <br /> <br />higher elevation in <br />If there is rock on the <br />could be constructed and a <br /> <br />Potential Problems With the Corrugated Metal Pipe - <br /> <br />1. <br /> <br />Placement - <br />the condu it <br />compacted. <br />occur. <br /> <br />The conduits ought to be carefully placed and the fill around <br />should be selected NON-PERMEABLE material properly <br />If the above items are not adhered to, a piping failure could <br /> <br />I <br /> <br />2. Strength Limits - The corrugated metal pipes have a strength limit. The <br />cover (height of embankment over the conduit) is limited, depending on <br />the size (diameter) of the conduit, the gage (thickness of the metal). <br />If the fill limit is exceeded, the conduits could collapse and cause the <br />slide mass to fail. <br />