2018-12-26_REVISION - M2008078 (31)

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4. Profile of Backfill Slope: The SB backfill slope and trench bottom shall be sounded at the beginning and end of each shift and converted to an as-built drawing. This drawing shall be reviewed daily as an indication of trench collapse, excessive settlement or sloughing. I. A qualified off-site laboratory shall be engaged by the Contractor to perform the permeability test called for in Table 1. J. Flexible wall permeability tests will be conducted on samples of the backfill to determine compliance with these specifications. Samples of the SB backfill will be obtained from the mixing area and will be sent to the off-site laboratory for testing. The test parameters will be as follows: 1. Average Effective Confining Stress=5 psi. 2. Hydraulic Gradient= 10 K. Documentation 1. Results of all tests performed will be recorded on forms acceptable to the Engineer. These forms will be available to the Engineer at all times for his/her inspection. Copies of all Contractor- required quality control documents will be submitted daily to the Engineer for his verification. 2. Results of all Construction activities shall be recorded daily on a form acceptable to the Engineer. At a minimum, these forms are to include: a. The project station both at the starting and ending location for each day for the following: i. Top of backfill ii. Toe of backfill iii. Last completed set b. Verified area of excavated material c. Contractor's start and stop work times d. Contractor's activities e. Set summaries that include: i. Start and stop time for excavation of the set ii. Depth to bedrock iii. Depth to bottom of key iv. Description of bedrock 3. An as-built profile drawing of the trench bottom and backfill slope shall be continuously maintained by the Contractor. The profile shall indicate the extent of excavation and backfill at the end of each working day. The daily profile shall be drawn in an electronic format or by hand. L. Performance testing of the completed slurry wall will be completed by the Owner's Representative in accordance with the"State Engineer Guidelines for Lining Criteria for Gravel Pits,"August 1999, Section 3.1. These guidelines stipulated a 90-day liner test to determine if the slurry wall keyed into the bedrock will meet the performance standards defined by the State Engineer,thereby releasing the Owner from augmentation responsibilities for the gravel pit. The testing consists of performing a 90-day liner test, used to determine the water balance to demonstrate the inflows(precipitation, groundwater) and outflows(evaporation). 31 66 17-11 Prowers Aggregate Operators, LLC West Farm Pit Phase 2 Slurry Wall Soil-Bentonite Slurry Walls