公路工程施工期的环境保护监理

对于生态影响较大的项目,重点发生在施工建设期,为了有效地控制工程施工阶段的生态环境影响和环境污染,开展公路工程施工期的环境保护监理工作尤其重要。本文结合工程环境监理工作实践,简要分析了公路工程施工期的环境保护监理要点。     

尼尔基水利枢纽施工干扰区生态环境修复与景观规划设计

大型水利工程的建设无疑为人们的生产生活带来了安全与保障,但其施工对生态环境的破坏同样不可小觑。本文结合尼尔基水利枢纽施工干扰区的实际情况,探讨水利枢纽施工干扰区生态环境修复与景观规划设计的理念与指导思想,从植物选择、水体处理与分区设计3个方面介绍了尼尔基水利枢纽施工干扰区生态环境修复与景观规划设计的主体方案构思。     

环境建设样板城内涵及评价指标体系研究

探讨了环境建设样板城提出的背景,提出环境建设样板城的基本概念及内涵,确定了环境建设样板城评价指标体系的制定原则,建立了由五大类九十项指标构成的环境建设样板城评价指标体系.     

Numerical investigation and analysis of indoor gas explosion: A case study of “6·13” major gas explosion accident in Hubei Province,China

Taking the ' 6·13 ′ major gas explosion accident in Shiyan, Hubei Province, China as an example, three problems were studied in this work: (1)The determination of the volume of natural gas involved in the explosion; (2)The propagation process of shock wave inside the building and the damage evolution process of the accident-related building; (3)The overpressure and fragment injury to the person outside the building. Through the numerical simulation in ANSYS/LS-DYNA software, the volume of natural gas involved in the explosion is determined to be 10240 × 1400 × 400 cm (length × width × height) from three perspectives: the damage to the building, the distribution of overpressure inside the building, and the TNT equivalent of the explosion energy. The simulation results are in good line with the accident, which verifies the effectiveness of the scheme and the accuracy of the numerical model. Based on the reasonable filling scheme, the propagation process of shock waves inside the building, the damage evolution process of the building, and the injury ranges of overpressure and fragments outside the building are analyzed. It can be found that the propagation of shock waves in confined space is complex and variable. The explosion shock waves are first reflected and superimposed in the watercourse, resulting in pressure rise. At about 8ms, the shock waves rushed into the first-floor space of the building, and the maximum overpressure was about 0.56 MPa. At about 50 ms, the shock waves rushed into the second-floor space, and the maximum overpressure was about 0.139 MPa. The first and second-floor slabs and infilled walls were almost completely destroyed. The interior walls of the infilled walls are mainly collapsed, and the exterior walls are ejection around the building as the center. The peak displacement and peak velocity of the interior walls of each floor are about 15% of the exterior walls. The fragments which cause fragment injury mainly come from the retaining wall above the watercourse, the maximum velocity is about 89 m/s, and the maximum displacement is 8.9 m. The safety distance of fragment injury is about 8.8 m, while the safety distance of overpressure injury is about 4.6 m. The lethal distance of fragment injury is greater than that of overpressure injury. Compared with the distance between different damage levels of overpressure injury, the difference in fragment injury is small. Therefore, the safety assessment at the engineering level only needs to consider the safety distance of fragment injury. This study can provide suggestions for evaluating the damage of natural gas cloud explosions in confined spaces and is helpful for accident investigation and safety protection.     

Using thermal analysis with kinetic calculation method to assess the thermal stability of azo compound on construction materials

The application of construction polymers in engineering and alternative materials has always occupied a place in the market. In the production process of polymer resins, initiators can be used to lower the polymerization reaction energy threshold, which can improve reaction efficiency and reduce energy loss. However, as a commonly used energetic substance in the polymerization process, azos have caused related process hazards due to their exothermic characteristics. Because of this, it is essential to examine and analyze the thermal hazard characteristics of emerging azo substances, such as 2-cyanopropan-2-imemicarbazide (CABN). Although previous literature performs the calculation on related thermal hazard parameters of CABN, there is still exists a void for discussion in estimating the reaction model to avoid analogous hazards and enhance the existing thermal analysis. Based on the past literature, the reaction model is improved with thermogravimetric analysis as evidence. The revised thermal hazard parameters are calculated as the basis of control and mitigation measures, the kinetic model is used to estimate the modified safety parameters, and in the judgment of the runaway reaction, the critical temperature of the runaway is found by analyzing the influence of slight changes in ambient temperature on the reaction temperature. The results show that the critical temperature that causes CABN to enter the runaway reaction is delayed, and the hazard is lower than in the storage situation. Therefore, the thermal hazard to CABN mainly focuses on the safety environment and measures during storage.     

Factors influencing the implementation of a safety management system for construction sites

The objective of the study was to determine the influential safety factors that governed the success of a safety management system for construction sites. The number of incidences among construction workers and the level of awareness on matters concerning safety were also determined. The study involved a self-administered three-part questionnaire among the workers and interviews with industry experts involved in brick-laying, concreting and in related assorted trades. Part A of the questionnaire concerned personal particulars, Part B involved training and experience and Part C was based on 28 industry-accepted safety factor elements. The construction sites ranged from high rise buildings, landed houses and infrastructure renovation. The sample size was 275. From the survey it was found that the most influential safety factor was personal awareness followed closely by communication. Suggestions and recommendations on equipment design and improved work practices and procedures to improve the efficiency and productivity of construction workers were proposed. Management was urged to get their workers better informed about safety matters.     

A fuzzy risk assessment approach for occupational hazards in the construction industry

The techniques in the construction industry have been improved due to the rapid development of science and technology. However, the constructional hazards are not decreased as expected. To reduce or prevent occupational hazards in the construction industry, a fuzzy risk assessment method was proposed to provide a prevention and improvement technique against occupational hazards. This method used two-stage quality function deployment (QFD) tables to represent the relationships among construction items, hazard types and hazard causes. A fuzzy analytic network process (ANP) method was developed to identify important hazard types and hazard causes. Failure modes and effect analysis (FMEA) was performed to assess the risk value of hazard causes based on the fuzzy inference approach. The proposed method was applied to a telecom engineering company in southern Taiwan. The performance evaluation result indicated that this method can provide satisfactory risk assessment values of hazard causes and relevant improvement strategies.     

Potential utilization of riverbed sediments by hydrothermal solidification and its hardening mechanism

Hydrothermal solidification of riverbed sediments (silt) has been carried out in a Teflon (PTFE) lined stainless steel hydrothermal apparatus, under saturated steam pressure at 343–473 K for 2–24 h by calcium hydrate introduction. Tobermorite was shown to be the most important strength-producing constituent of the solidified silt. A longer curing time or a higher curing temperature was shown to be favorable to the tobermorite formation, thus promoting strength development; however, overlong curing time (24 h) seemed to affect the strength development negatively. The hardening mechanism consisted of the crystal growth/morphology evolution during the hydrothermal process. The species dissolved from the silt were precipitated first as fine particles, and then some of the particles seemed to build up the rudimental morphology of calcium silicate hydrate (CSH) gel. The CSH gel, with precipitated particles, appeared to cause some reorganization within the matrix, which made the matrix denser and thus gave an initial strength development. Tobermorite, transformed inevitably from the CSH gel, reinforced the matrix with its interlocked structure, and thus further promoted the strength development.     

沈阳市突发性环境污染事故应急监测能力建设现状分析

分析了沈阳市应急监测工作现状,指出了存在的问题,并指明了今后的发展方向。