CCEER-19-01: Improving Strain Wedge Model Capabilities in Analyzing Laterally Loaded Drilled Shafts in Cemented Soils
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Authors
Saint Pierre, E.
Elfass, Sherif
Watters, R.
Norris, Gary
Ashour, Mohamed
Issue Date
2019-03-01
Type
Report
Language
Keywords
CCEER
Alternative Title
Abstract
Cemented soils deposits located in Las Vegas valley have long been a challenge for engineers. These deposits can withstand considerable loads. They are, however, difficult to model or predict using typical site investigation techniques. For engineering purposes, these cemented soils, also commonly referred to as Caliche, are difficult to quantify their thickness, strength and lateral extent. This erratic and heterogeneous nature can result in inconsistent design and performance of foundations. This report presents a new material model for cemented soils in the Las Vegas region. The material model was developed using results obtained from unconfined compressive strength tests conducted on 53 cored samples, with different levels of cementation. The model, which generates the stress-strain relationship of cemented soils, recognizes three cementation levels and allows the user to account for closure of fractures if desired. Laboratory shear and primary wave velocities were measured for all samples. In addition, field shear wave velocity of the site where the samples were obtained, was assessed using Refraction Microtremor (ReMi) and Multichannel Analysis of Surface Waves (MASW) methods. Relationships between lab shear wave velocity, material unit weight, unconfined compressive strength and Young's Modulus are presented. Furthermore, a preliminary correlation between field and lab shear wave velocities is introduced. The model along with the derived relationships were implemented in Strain Wedge Model (SWM) to assess the performance of laterally loaded shafts embedded in cemented soils. Comparison between SWM prediction and field performance of laterally loaded shafts during 1996 load test program is presented.
Description
Report No. CCEER-19-01
Citation
Publisher
License
In Copyright