The proposed development at the site included replacement of the existing sanitary sewer line with a larger diameter vitrified clay pipe (VCP). The existing pipe diameter ranged approximately from 10 inches to 18 inches from Garfield Avenue to 8th Street while the proposed replacement VCP ranged approximately from 15 inches to 24 inches. The existing and future VCP lines were located at the depths ranging from 13 to 19 feet below the ground surface (bgs) along the segment of the project and included periodic manholes that extended up to ground surface.
GAI’s scope of work comprised of conducting field exploratory borings, performing laboratory tests on collected samples, and preparing a final geotechnical report with our recommendation on the deep trench excavations and utilizing shoring.
Geo-Advantec, Inc. provided geotechnical instrumentation and monitoring for the City of Los Angeles Trunk Line South, Unit 4, Phase 2. The project purpose was studying and monitoring the displacement of the deep tunnel shafts’ walls and settlement of the underground tunnel due to construction of a new sewer line. To monitor the movement and settlement during the construction, GAI installed four inclinometers, each between 25 to 40 feet deep, and six vertical/deep extensometers of about 70 feet deep. The reports of instrumentation readings were prepared and provided to the project team on a daily base.
The City intended to design and construct an on-site storm-water disposal system. The system would collect and infiltrate Garey Avenue runoff into the ground. Geo-Advantec scope of work included conducting several exploratory borings at the designated locations, conducting SPT and sampling at 3 feet intervals for the substrata profile determination, collecting disturbed/bulk samples of the encountered subsurface material, conducting three percolation tests at a depth targeting the most permeable layer, performing laboratory testing on the selected soils samples, reviewing the field data and the laboratory test results, performing engineering analyses, and preparing a final geotechnical evaluation report that included results of our field and laboratory testing and determined infiltration rates at the site. Our team completed the project in less than two weeks.
As an environmental friendly approach, the City intended to design and construct on-site storm water disposal systems in several streets. Geo-Advantec was employed to perform a geotechnical investigation at Cienega Avenue, Monte Vista Avenue and Via Verde Street. The total length of the project was about 3 miles. We conducted 15 borings using a hollow stem drilling rig and the borings were advanced to a maximum depth of 25 feet. The laboratory tests were performed on the soil samples collected from different layers. Based on the tests results analysis, the preliminary permeability of soil layers at each location was determined and reported. We provided the city with the final profile of soil stratigraphy and their permeability properties. The report assisted the City in determining the future possibilities of using on-site disposal system and would be used as a guide in determining the locations of future field percolation tests.
The project was intended to help protect public health by replacing aging infrastructure and help prevent groundwater contamination. The project also implemented the sewer master plan by taking advantage of an opportunity to upgrade the previous 12-inch sewer lint to a 15-inch line as recommended by the plan.
Geo-Advantec provided during construction soils and asphalt testing services to the City. The grading work consisted of excavation, backfilling, compaction, and asphalt paving for the proposed sewer line, within the approximately 1,700 linear feet length of the project.