Technical review of the stability of the rock slope and penstock foundations of the 1500-ft long, vertical drop power penstock. Also performed independent stability computation of the ?rock toppling? model and tie-back requirements. Also, developed and evaluated various alternatives to the original conceptual design to optimize expenditures without compromising the project safety.

Project Engineer in charge of the following investigations and designs:

• Performed Menard pressure-meter and plate bearing tests on the Castaic siltstone rock to assess deformation properties and limiting stresses for the final design of surge chamber.
• Performed rock deformation computations for the excavation of the 1,250 MW capacity pump-storage powerhouse (assessment of rock rebound and recompression due to excavation and subsequent reloading).
• Performed final design of the support of the bifurcation structure (30-ft diameter Angeles tunnel outlet bifurcating into six 12-ft diameter power penstocks and one 6-ft diameter starter unit penstock). The structural loads due to the penstocks were 22,000kip uplift plus 47,000 kip horizontal load against the steel penstock of Angeles Tunnel.
• Performed final design analyses of the 12-ft diameter power penstocks at the entrance to the powerplant. The 1-3/4 inch thick steel penstocks at this point were to be subjected to 750 psi internal pressure and 120-ft of backfill soils and switch yard. In addition to closed form stress and deformation analyses, Dr. Marachi performed a detailed finite element analysis, which he later verified through a physical field model test. (The difference between the physical model and finite element model was found to be less than 15 percent).
• Designed alternative lean concrete mix designs for penstock and powerhouse backfills. Performed laboratory and field tests to optimize the design.
• Prepared monitoring manual for the penstocks to check the stresses and deflections during various operational loading scenarios. The manual included design, installation, operations and interpretations of all instrumentations.
• Designed, installed and performed all monitoring activities (i.e., extensometers, slope indicators, stressmeters, piezometers, etc.) related to performance of excavated rock slopes, bottom half of the power house excavation, and computations related to rock stress relaxation and recompression due to reloading.

Project Manager for the geological and geotechnical investigations and design recommendations for the foundation of the 50mw power plant and the 10-ft diameter power penstock and associated anchor blocks, and design and recommendations of anchored tie-back system for stabilization of the slope and incipient slide directly affecting the penstock and power plant.

Principal-in-Charge of the drilling and geological investigations along the 18,000 ft long tunnel. Investigations delineated rock conditions at the tunnel grade and portal conditions. Also provided design recommendations for the tunnel boring machine (TBM) and localized lining requirements.

Review consultant for the evaluation of properties of fractured rock and review and recommendation of design modification and construction procedures of the power penstock.