A novel solution for ground reaction curve of tunnels in elastoplastic strain softening rock masses

Ground Reaction Curve (GRC) is one of the most important elements of convergence-confinement method generally used to design tunnels. Realistic presentation of GRC is usually assessed based on the advanced rock strength criteria, also, rock mass behavior (including plasticity and softening treatments). Since taking these parameters into ac­count is not simply possible for practitioners and needs complicated coupled theoretical-numerical solutions, this paper presents a simple novel approach based on Evolutionary Polynomial Regression to determine GRC of rock masses obeying both Mohr-Coulomb and Hoek-Brown criteria and strain softening behaviors. The proposed models accurately present support pressures based on radial displacement, rock mass strength and softening parameter (determination coefficient of 97.98% and 94.2% respectively for Mohr-Coulomb and Hoek-Brown strain softening materials). The ac­curacy of the proposed equations are approved through comparing the EPR developed GRCs with the ground reaction curves available in the literature. Besides, the sensitivity analysis is carried out and in-situ stress, residual Hoek-Brown’s m constant and residual dilation angle are introduced as parameters with the most influence on the support pressure in Hoek-Brown and peak and residual geological strength index are the most affective parameters on the support pressure of tunnels in the strain softening Mohr-Coulomb rock mass

Investigating availability and distribution trend of human resources affiliated to the Ministry of Health and Medical Education in Iran from 2009 to 2015

Background and Objectives: Quantitative and qualitative improvement of human resources inequality have a significant effect on achievement to health system goals. The purpose of this study was to investigate the trend of geographic, supply, and gender distribution inequality of human resources of the Ministry of Health and Medical Education (MOHME) in Iran. Methods: In this descriptive study, the trend of human resources of the Ministry of Health during the years 2009-2015 was investigated based on gender, level of education, and type of employment. In order to study the inequality, Lorenz curve and Gini coefficient index were used. Data were collected from the Human Resources Office of the Deputy of Management Development and Resources of the MOHME and analyzed by Excel 2013 and Stata-14 software. Results: In the present study, women had the highest portion with a growth rate of 6.66% in 2015 and a Gini coefficient of 0.29 except in 2011. The highest and lowest growth rate compared to the base year in 2010 was related to specialist doctors (83.12) and general practitioners (-19.61), respectively. The lowest and highest Gini coefficient was related to the associate degree (0.26) and subspecialty (0.45), respectively. Conclusion: The present study was the first study to investigate the trend of changes in the human resources characteristics of the MOHME at a national level. Since this study only considered the quantity of the trend of human resources changes, it is recommended that the quality of human resources be investigated in the future studies