دانلود رایگان مقاله انگلیسی ارزیابی تاثیر روانگرایی خاک بر ساختمان کم ارتفاع در زلزله Meinong - اشپرینگر 2017

Abstract

This paper presents major preliminary observations on the liquefaction-induced damages in the Meinong earth‑ quake (ML = 6.4). The severe damages to buildings centered on Huian and Sanmin Streets in Tainan City where the places were reclaimed fsh or farm ponds with poor construction quality from many decades ago. To better under‑ stand the efect due to the soil liquefaction at these sites, the information provided by the in situ 13 Standard Pen‑ etration Test boreholes and 5 Cone Penetration Test soundings accompanying with the PGAs derived from the near seismographs was used to conduct the soil liquefaction evaluation by the Seed method (Seed et al. in J Geotech Eng ASCE 111(12):1425–1445, 1985) when subject to the Meinong earthquake. The liquefaction potential index (LPI) was then evaluated accordingly. From the results, it was found that the estimated damage severity was not consistent to the feld conditions if the local site efect was not taken into account. To better refect the site response in such sites, the sites’ PGAs in the PGA contour map were multiplied by 1.5 times to quantify the amplifcation efects due to the soft geological condition. In addition, the PGAs based on other simple approaches were evaluated as well for com‑ parison. Besides, the efects of fnes content and magnitude scaling factor were also discussed in this paper. After that, several common simplifed methods were also used to calculate the LPI when subject to the Meinong earthquake in order to evaluate the applicability of these simplifed methods.

Conclusion

Tis paper discussed the liquefaction-induced damage to buildings that occurred during the Meinong earthquake. From site investigations, we determined that the formations of the liquefed sites always exhibit a very soft clay layer below the saturated sandy soils. Te foundation load is mainly supported by the sandy soils and a preshear (deviatoric) stress existing in the foundation soil of the footing before earthquake. Te soil is easier to reach the failure state due to the additional shear force and the generation of the excess pore water pressure triggered by the earthquake excitation and cause large settlement and deformation. During the shaking of the earthquake, the excess pore water pressure is generated and decreased the strength of the saturated sandy soils. When the softened sandy soils beneath the spread foundation cannot bear the deviatoric stress induced by the loading of the surface building as well as the additional shear force due to the seismic loading, the foundation bearing layer will be squeezed out laterally and upward. Ten, the foundation load is transferred to the soft clay beneath the saturated sandy soils, which induces more settlement of the building. Note that if the weight of the surface building is uneven like the case shown in Fig. 4, the diferential settlement can be observed in case of the foundation bearing layer being liquefed during earthquakes.