http://ssu.ac.ir/cms/fileadmin/user_upload/Moavenatha/Mposhtibani/Mdaftar_fani/KhadamatKarkonan/Articles/EN/Tust_Vol_16_4_247-293.pdf

Seismic design and analysis of underground structures

Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate‐ and large‐magnitude earthquakes trigger landslides, ranging from small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to centuries later, and flood mountain valleys for hundreds of kilometers downstream. Landslide deposits on slopes can remobilize during heavy rainfall and evolve into debris flows. Cracks and fractures can form and widen on mountain crests and flanks, promoting increased frequency of landslides that lasts for decades. More gradual impacts involve the flushing of excess debris downstream by rivers, which can generate bank erosion and floodplain accretion as well as channel avulsions that affect flooding frequency, settlements, ecosystems, and infrastructure. Ultimately, earthquake sequences and their geomorphic consequences alter mountain landscapes over both human and geologic time scales. Two recent events have attracted intense research into earthquake‐induced landslides and their consequences: the magnitude M 7.6 Chi‐Chi, Taiwan earthquake of 1999, and the M 7.9 Wenchuan, China earthquake of 2008. Using data and insights from these and several other earthquakes, we analyze how such events initiate processes that change mountain landscapes, highlight research gaps, and suggest pathways toward a more complete understanding of the seismic effects on the Earth's surface.

Earthquake-Induced Chains of Geologic Hazards: Patterns, Mechanisms, and Impacts

A frequency-domain parametric study using generalized consistent transmitting boundaries has been performed to evaluate the significance of topographic effects on the seismic response of steep slopes. The results show that the peak amplification of motion at the crest of a slope occurs at a normalized frequency H /λ = 0.2, where H is the slope height and λ is the wavelength of the motion. The importance of the natural site frequency is illustrated by the analysis of a stepped layer over a half-space. It was found that the natural frequency of the region behind the crest can dominate the response, relative to the topographic effect, for the conditions studied. Moreover, the effect of topography can be handled separately from the amplification due to the natural frequency of the deposit behind the crest of the slope. This concept of separating the amplification caused by topography from that caused by the natural frequency is advantageous to the development of a simplified method to estimate topographic effects.

Topographic effects on the seismic response of steep slopes

Synthesis and characterization of fly ash modified mine tailings-based geopolymers

A new seismic design philosophy is illuminated, taking advantage of soil “failure” to protect the superstructure. Instead of over-designing the foundation to ensure that the loading stemming from the structural inertia can be “safely” transmitted onto the soil (as with conventional capacity design), and then reinforce the superstructure to avoid collapse, why not do exactly the opposite by intentionally under-designing the foundation to act as a “safety valve” ? The need for this “reversal” stems from the uncertainty in predicting the actual earthquake motion, and the necessity of developing new more rational and economically efficient earthquake protection solutions. A simple but realistic bridge structure is used as an example to illustrate the effectiveness of the new approach. Two alternatives are compared : one complying with conventional capacity design, with over-designed foundation so that plastic “hinging” develops in the superstructure; the other following the new design philosophy, with under-designed foundation, “inviting” the plastic “hinge” into the soil. Static “pushover” analyses reveal that the ductility capacity of the new design concept is an order of magnitude larger than of the conventional design: the advantage of “utilising” progressive soil failure. The seismic performance of the two alternatives is investigated through nonlinear dynamic time history analyses, using an ensemble of 29 real accelerograms. It is shown that the performance of both alternatives is totally acceptable for moderate intensity earthquakes, not exceeding the design limits. For large intensity earthquakes, exceeding the design limits, the performance of the new design scheme is proven advantageous, not only avoiding collapse but hardly suffering any inelastic structural deformation. It may however experience increased residual settlement and rotation: a price to pay that must be properly assessed in design.

/pdf/soil-failure-can-be-used-for-seismic-protection-of-5egeqouxed.pdf

Soil failure can be used for seismic protection of structures

http://www.mie.uth.gr/gipipe/publications/SDEE_2010-Buried_Pipes_I.pdf

Finite element analysis of buried steel pipelines under strike-slip fault displacements

http://www.mie.uth.gr/gipipe/publications/SDEE_2012-Buried_Pipes_II.pdf

Mechanical behavior of buried steel pipes crossing active strike-slip faults

Pipe–soil interaction and pipeline performance under strike–slip fault movements

http://ssi.civil.ntua.gr/downloads/journals/1992-SDEE_Seismic%20analysis%20and%20design%20of%20rockfill%20dams%20state%20of%20the%20art.pdf

Seismic analysis and design of rockfill dams: state-of-the-art*

http://ssi.civil.ntua.gr/downloads/journals/1985-SDEE_A%20class%20of%20inhomogeneous%20shear%20models%20for%20seismic%20response%20of%20dams%20and%20embankments.pdf

Panos Dakoulas

Papers

Finite element analysis of buried steel pipelines under strike-slip fault displacements

Mechanical behavior of buried steel pipes crossing active strike-slip faults

Pipe–soil interaction and pipeline performance under strike–slip fault movements

Seismic analysis and design of rockfill dams: state-of-the-art*

A class of inhomogeneous shear models for seismic response of dams and embankments