Stability Analyses of a Levee on Deep-Mixed Columns, Plaquemines Parish, Louisiana

摘要

The U.S. Army Corps of Engineers recently completed reconstruction of a section of flood protection levee known as the P24 project, which included installation of shear walls along a portion of the alignment. The shear walls were created using the dry method of deep mixing. Two-dimensional stability analyses were performed using limit-equilibrium and numerical methods to evaluate the factor of safety of the structure and assess the potential for racking. Ordinary limit equilibrium analyses do not account for potential failure modes other than shearing; whereas, numerical stress-strain analyses can account for other failure modes, such as racking of the deep mixed material due to slipping along vertical joints between adjacent columns in the shear panels. Numerical analyses were completed for varying numbers of weak joints as well as for a range of joint strength values to evaluate the sensitivity of the results to these factors. The results show that, for the conditions used to represent this project, the racking failure mechanism ceases to control performance at vertical joint efficiencies greater than or equal to 30%.