Evaluation of Existing P-Y Models For Caliche Based on Numerical Analysis of Raiders Stadium Lateral Load Tests-PPT Presentation

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The study evaluated whether existing rock p-y models can predict the lateral response of caliche, a hard, calcium-carbonate-cemented material common in the Las Vegas Valley. Because no site-specific caliche p-y model is available, researchers compared the Reese and Nyman vuggy limestone model with the McVay and Niraula Florida limestone model.<br /><br />Four lateral load tests on 24-inch-diameter, approximately 66.5-foot-long continuous-flight-auger piles at the Raiders Stadium site were simulated using NVShaft. The piles were tested under loads up to 90 kips; one test included an additional cycle reaching 187 kips. Predicted pile-head deflections were compared with measurements using normalized error. The analysis also considered caliche depth and acknowledged uncertainty in its material properties: the investigation reported refusal SPT values, while the study assumed a caliche unconfined compressive strength of 12 ksf.<br /><br />Both limestone models produced small normalized errors at design load levels, suggesting they can provide reliable predictions within that range. Overall, the vuggy limestone model predicted the measured lateral responses somewhat better than the Florida limestone model. A stiff-clay model was excluded after preliminary analyses showed substantial disagreement with the test results.<br /><br />The findings support using the evaluated rock p-y models for preliminary analysis of caliche, but the limited material-property data and absence of a site-specific model remain important constraints.

Keywords

caliche

rock p-y models

lateral load tests

pile-head deflection

Reese and Nyman model

McVay and Niraula model

NVShaft

Raiders Stadium

limestone model

unconfined compressive strength