مهندسی عمران شریف (Nov 2018)
DYNAMIC RESPONSE OF INCLINED MICRO-PILES IN LAYERED SOILS
Abstract
Complexity forces in deep foundations, such as piles and micro-piles to dynamic analysis, are most important parts of analyzing. Low effect seismic destruction is considered to run this type of foundations. In the present article, Micro-piles modeling have been investigated for double groups by applying different angles, including $15^0$, $20^0$, $25^0$, $30^0$, $90^0$ using ABAQUS software. Soil environment has been modeled in both Single-layer and that which is layered with consider making two types of elastic and plastic behaviors with Drucker-Prager model. In both cases, is investigated the effects of soil with soil and micro-pile interaction have been investigated, on micro-piles behavior. Dynamic analysis was carried out with the vertical load to cap the micro-piles and by entering acceleration onto the model floor with assuming linear attenuation by El-Centro earthquake record and sinusoidal harmonic acceleration. At the end, evaluation of these changes in stress distribution in the soil, the relative displacement, change of bending moments, and axial forces for homogeneous and non-homogeneous soils has been carried out. Dynamic analyses have shown that angel of micro-piles from vertical to25\u{02da} is the cause of the reduction of the stress level in the soil. The maximum bending moments and axial forces occur near the cap of the micro-pile and continue the depth of micro-piles; this change is minimal. This subject states proposes micro-pile importance in reducing displacement, especially in cases of the soil with layers. Due to damping within the upper layers of soil and micro-pile's cap, soil stress distribution has increased; moreover, due to the effect of gravity in more depth of micro- pile, tensions have been reduced in the surrounding soil.In homogeneous soil, 20- degree angle is suitable for micro-pile angle and the angle of the non-homogeneous soil is 15 degrees for a better distribution of stress. Comparing the relative displacement values and uplift values of homogeneous and heterogeneous soils surrounding the micro-pile 20- degree angle to the right angle is placed in the soil.
Keywords
