01514855

Component

The practice of using drilled shafts to stabilize an unstable slope has been adopted for many years. However, there may be conditions where the only use of drilled shafts may not be adequate due to the inability to provide the required global factor of safety; or due to a huge construction cost of drilled shafts. For the optimized design dealing with stabilization of a failed slope or unstable slope, the combination of anchors and drilled shafts may be utilized as an option. There has been no design method developed in the past to permit systematic reliability-based design for using a combination of anchors and drilled shafts for slope stabilization. In this paper, the Monte Carlo simulation technique was used in conjunction with a previously developed deterministic computational program, in which the limiting equilibrium method of slices was modified to incorporate arching effects of the drilled shafts in a slope. Uncertainties of anchor force and soil parameters for each soil layer in a slope were considered using pertinent statistical descriptors, including mean, coefficient of variation (c.o.v.), and distribution function. Model errors due to the semi-empirical predictive equation used for the load transfer factor for characterizing the drilled shaft induced soil arching effects were considered by statistics of bias. A PC-based program called P-A-UASLOPE has been coded to allow for handling of complex slope geometry, soil profile, and ground water conditions. A design example is presented to illustrate the application of the P-A-UASLOPE program in the design of an anchor-drilled shaft/slope system. The importance of using reliability based computational method was illustrated by showing that a single value of Factor of Safety chosen in the deterministic approach may not yield the desired level of reliability, as uncertainties of soil parameters, anchor force and model errors cannot be accounted for systematically.

This paper was sponsored by TRB committee AFP10 Engineering Geology.

01503729

14-3959

English

17p

2014

Transportation Research Board 93rd Annual Meeting

Digital/other

Figures; References; Tables

Anchors (Structural connectors); Monte Carlo method; Reliability; Simulation; Slope failure; Slope stability; Soil profiles

Drilled shafts

Design; Geotechnology; Highways; I20: Design and Planning of Transport Infrastructure; I42: Soil Mechanics

Transportation Research Board Annual Meeting 2014 Paper #14-3959

TRIS, TRB, ATRI

Jan 27 2014 3:22PM