Simple reliability analyses, involving neither complex theory nor unfamiliar terms, can be used in routine geotechnical engineering practice. These simple reliability analyses require little effort beyond that involved in conventional geotechnical analyses. They provide a means of evaluating the combined effects of uncertainties in the parameters involved in the calculations, and they offer a useful supplement to conventional analyses. The additional parameters needed for the reliability analyses—standard deviations of the parameters—can be evaluated using the same amount of data and types of correlations that are widely used in geotechnical engineering practice. Example applications to stability and settlement problems illustrate the simplicity and practical usefulness of the method.

Factors of safety and reliability in geotechnical engineering

Performance of industrial by-products in controlled low-strength materials (CLSM).

The field vane (FV) has traditionally been utilized to obtain profiles of undrained shear strength in soft to medium clays. After some 40 years of experience with FV results, it has been suggested ...

Profiling of overconsolidation ratio in clays by field vane

During 19771978 a series of 25 ft wide 8 m by 30 ft deep 9 m sewer culverts were built in the Islais Creek Basin near San Francisco Bay. The sheetpile wall supported excavations for the culverts we...

Measured behavior of braced wall in very soft clay

To investigate the time-dependent stress-strain behavior of Hong Kong marine deposits (HKMD), three types of triaxial tests have been conducted under both compression and extension states. The first is conventional undrained shear tests at different strain rates ranging from 0.0025 to 0.25%/min. The second type is stress relaxation tests. The last type is undrained creep tests. The results are reported in this paper. One order increment of logarithmic strain rate causes about 5 to 9% increase of undrained shear strength. In stress relaxation tests, the pore-water pressure increase is about 10% of the consolidation pressure under extension states. A power law equation is presented to calculate the decay of the deviator stress in relaxation. In multi-stage triaxial creep tests, the log(strain rate)-log(t) relationship of the lower stress level is linear. The slopes of these lines are dependent on current deviator stress as well as stress history.

Time-dependent stress-strain behavior of soft hong kong marine deposits

The failure of a 90-ft-high (27 m) underwater slope in San Francisco Bay is used to assess the accuracy of conventional laboratory and field vane shear tests for measuring the undrained strength of a normally consolidated clay. The net effect of systematic errors due to disturbance, anisotropy, cap and base restraint, and the use of triaxial rather than plane strain tests was apparently small in this case, but the reduction of undrained strength due to creep under continued loading was significant, and the effect of creep strength loss can explain the discrepancy between the strength measured in the laboratory and that modified at failure in the field. Empirical corrections for measured strength are recommended

Albert L. Buchignani

Papers

Failure of Underwater Slope in San Francisco Bay