Construction and Long-Term Performance of Transportation Infrastructure Constructed Using EPS Geofoam on Soft Soil Sites in Salt Lake Valley ,
The Utah Department of Transportation (UDOT) and the Utah Transit Authority (UTA) have made extensive use of EPS embankment for several major interstate, light rail, and commuter railway embankments in Salt Lake Valley, Utah. Constructed between 1998 and 2001, the Interstate 15 Design Build Reconstruction Project involved the widening of interstate embankments within a 27 km narrow corridor and limited right-of-way. Approximately, 100,000 m of EPS fill was placed at various locations to minimize post-construction settlements of deep, compressible lake deposits. This paper presents results of long-term monitoring of EPS fills and comparison with other geotechnologies. Geofoam embankments had the best overall settlement performance of the technologies monitored. Gap closure and deformation of the geofoam embankment due to placement of the load distribution slab and overlying roadway materials was about 1% of the embankment height. In addition, at 3300 South Street, the foundation soil settled about 15 mm due to placement of the embankment and overlying loads. The face of the embankment settled an additional 25 mm in a 5-year period due to additional pressure of a 1.5m toe berm placed at the base of the tilt-up wall. Total post-construction settlement (foundation settlement and geofoam creep) is expected to be about 50 mm at the wall face for a 10-year postconstruction period. The trend of post-construction settlements suggest that geofoam embankments are performing as designed and will meet the 50-year post-construction deformation limit of 1% creep strain. Overview of the I-15 Reconstruction Project The Utah Department of Transportation (UDOT) togeth er with Wasatch Constructors finished the $1.6 billion reconstruction of Interstate 15 (I -15) that runs through Salt Lake City, Utah in 2001 just prior to the start of the 2002 Winter Oly mpics. The interstate embankment was widened from eight lanes to ten general-purpose lan s, plus two high occupancy vehicle lanes, within an existing north-south alignment that runs through the middle of the densely populated Salt Lake Valley. In this area, parts of the I-15 a lignment are located atop extensive deposits of relatively compressible lake sediments. Collateral consolidation settlement along this widened alignment had to be minimized to prevent differenti al settlement damage and subsequent
Performance of Lime Cement-Stabilized Soils for the I-15 Reconstruction Project: Salt Lake City, Utah
The application and performance monitoring of lime cement stabilization were studied for the Interstate-15 Reconstruction Project at 300 West Street in Salt Lake City, Utah. Lime cement columns (LCCs) were used to support a large mechanically stabilized earth (MSE) wall constructed over soft foundation soils and in close proximity to a commercial building. The Utah Department of Transportation has installed instrumentation at this site to measure the construction and postconstruction deformation within the treated zone and around the adjacent building. Also, total pressure cells have been installed atop the treated zone and in an adjacent untreated area to measure differences in load transfer. The use of LCC-stabilized soil has reduced the amount of primary settlement from about 1 m without treatment to about 0.2 m in the treated zone. Ground settlement at the nearest wall of the adjacent building has been about 5 cm total during a 2.5-year monitoring period with 3 of the 5 cm occurring during MSE wall construction and surcharge placement. Also, measurements indicate that the global stability of the MSE wall foundation has been notably improved. It is hoped that the data gathered from this array will provide a valuable case history of LCC performance for evaluation and modeling.
The Inca Occupation of the South Coast of Peru
like the others, however; it forks into several nearly parallel ravines of which the largest are Huayuri, Rio Grande-Palpa, Ingenio (called Collao in ancient times), Nasca proper (the ancient Caxamarca), Taruga, and Poroma. Due to peculiarities of the local topography, the irrigated areas in Ica and the ravines of Nasca are located inland, at the foot of the mountains, rather than at the mouths of the rivers as is more usual in Peruvian coastal valleys. No sharp natural or cultural boundary separates the valley of Chincha from the valleys of Cafiete (ancient Huarco and Runahuana), Asia, and Mala, the next valleys going up the coast to the northwest. At the other end of the area we are considering, however, there is a sharp break; beyond Yauca the Andean foothills reach out to the sea, natural conditions are quite different, and there are important differences in the archaeological picture as well. The historical sources which mention the south coast are not particularly helpful, except in so far as they provide us with a few dates. To begin with, no chronicler gives an explicit account of the political organization of the south coast at the time it came into contact with the Incas. It can, perhaps, be inferred from Cabello Balboa's statements about common policy toward the Inca invaders that there was some sort of political connection between the valleys of Mala, Cafiete, and Chincha, but the connection need have been no more than a temporary military alliance. Cabello makes no mention at all of Pisco. The valleys of Ica, Nasca, and 125