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Section 02210 <br /> EXCAVATION, BACKFILLING, AND COMPACTION FOR UTILITIES <br /> Groundwater shall be controlled to prevent softening of the bottom of excavations, or <br /> formation of"quick" conditions. Dewatering systems shall not remove natural soils. <br /> Release of groundwater to its static level shall be controlled to prevent disturbance of the <br /> natural foundation soils or compacted fill and to prevent flotation or movement of <br /> structures of pipelines. <br /> Additional dewatering requirements are specified in Section 02140, DEWATERING. <br /> B. Overexcavation <br /> Where the undisturbed condition of natural soils is inadequate for support of the planned <br /> construction, the Construction Manager will direct the Contractor to overexcavate to <br /> adequate supporting soils unless indicated otherwise. The excavated space shall be filled to <br /> the specified elevation with bedding or clean crushed rock as directed by the Construction <br /> Manager. At the wastewater treatment plant site, the excavated space shall be filled with <br /> CDF and crush rock as indicated. The quantity and placement of such material will be paid <br /> for as follows: <br /> 1. Overexcavation and refilling up to 6 in. below the specified trench bottom elevation <br /> shall be solely the Contractor's responsibility and expense. <br /> 2. Overexcavation and refilling in excess of 6 in. below the specified trench bottom <br /> elevation will be considered extra work in accordance with the Standard Construction <br /> Specifications Section 9, CHANGES AND CLAIMS. <br /> C. Trenching <br /> Make trench sides as nearly vertical as practicable except where sloping of sides is <br /> allowed. Sides of trenches shall not be sloped between the bottom of the trench and the <br /> elevation of the top of the pipe. Grade bottom of trenches accurately to provide uniform <br /> bearing and support for each section of pipe or conduits on undisturbed soil, or bedding <br /> material as indicated or specified at every point along its entire length except for portions <br /> where it is necessary to excavate for bell holes and for making proper joints. Dig bell holes <br /> and depressions for joints after trench has been graded. Dimension of bell holes shall be as <br /> required for properly making the particular type of joint to ensure that the bell does not <br /> bear on the bottom of the excavation. Trench dimensions shall be as indicated. <br /> D. Shoring and Sheeting <br /> Shore and sheet excavations 5 ft or greater in depth in accordance with Section 02160, <br /> EXCAVATION SUPPORT SYSTEMS. <br /> Walnut Grove Sewer Project (Conformed) 02210-7 SAO 160401 <br /> March 2008 <br /> n:Asa0160401\specs\wg con form\dic 2\02210.doc <br />