فهرست مطالب mohammad reza motahari

The main problem with saturated fine-grained soils is the slowness of consolidation procedure and the occurrence of large soil settlements. Generally, to expedite consolidation procedure, preloading method would be used along with prefabricated vertical drains. Soil improvement process under this condition would be subjected to design method and vertical drains’ modeling. In the current paper and to understand the consolidation behavior of clayey soils improved with vertical drains, a parametric study has been performed by PLAXIS 2D finite element software. The results are indicative of an increase in average consolidation degree from 74 to 84% after a period of 6 months through the reduction of vertical drains’ distances from 4.5 to 1.5m. Moreover, it became clear that an increase would be made in the rate of settlement, consolidation, and dissipation of excess pore water pressure through increase made in length and diameter of vertical drains and increase of their discharge capacity. Also, it became specified that increase of diameter is less effective on the expedition of consolidation procedure compared to that of distance reduction among drains.

Blast hole drilling and blasting are from among cost effective and economic methods of crushing the rock in civil projects, tunneling, as well as surface and underground mining. Ground vibration is the most important undesirable effect of blasting and if not controlled, it can lead to many damages. The paper is aimed at studying and prediction of effects of vibrations resulted from blasting on structure of dam on Dareh-Baq River. For this purpose, four empirical equations along with Artificial Neural Network (ANN) have been used to the aim of achieving a highly accurate model to predict vibrations of ground. Also, level of vibrations created would be compared through existing standards. According to the above goals, 73 blasting cases in Dareh-Baq River Dam area have been studied and required parameters as for prediction have been measured. From 73% of information related to blasting has been used to obtain empirical equation and also provide appropriate model in ANN; and, the remaining 27% of information have been used to specify performance and evaluate accuracy level of various models, in comparison to real values. After evaluation of the results, it became clear that ANN is of highest accuracy for prediction of vibrations resulted from blast. Also, in consideration of recorded vibrations and their comparison to existing standards, as well as distance of dam on Dareh-Baq River from location of blasting, energy from vibrations created will be dissipated and no undesirable effect would be imposed on dam structure.

Ballast shaking is one of the most significant adverse effects of explosion operations in construction projects and surface mines, and in case of control, it will lead to extensive damage to the surrounding structure. Therefore, accurate prediction of these vibrations is essential in minimizing its environmental effects. The goal of the current paper is to investigate and predict the results of the ballast operation on the Shur River dam structure. The application of the ANN as a powerful tool in predicting vibration generated from explosion operations has been studied. In addition to the ANN, experimental models have been used for this work. Different statistical criteria such as RMSE have been used to evaluate the performance of the proposed models in predicting vibrations. The results indicate that the values by the ANN are closer to real values and ANN has a much higher accuracy than other empirical models in predicting the vibration caused by the explosion operation.