本文地基施工中的施工事故的安全评价是通过LEC法来完成的，作业条件危险性评价法评价人们在某种具有潜在危险的作业环境中进行作业的危险程度，该法简单易行，危险程度的级别划分比较清楚、醒目。但是，由于它主要是根据经验来确定3个因素的分数值及划定危险程度等级，因此具有一定的局限性。而且它是一种作业的局部评价，故不能普遍适用。所以本文用其作简单的施工事故分析。关键词：施工组织；安全评价；事故树；LEC9466
Large foundations safe construction organization design
Abstract：In recent years, the development of urban architecture to the high-altitude , high-rise or high-rise building row upon row , based on the building 's foundation and construction of the increasingly high demand , more and more difficult construction , the attendant , construction safety problem is particularly prominent. In particular excavation, due to construction technology difficult, excavation and supporting long duration, site construction conditions and other reasons , resulting in a lot of accidents , so how to effectively curb the Foundation Pit accidents and disasters losses and reduce the environmental impact , has become an urgent need to focus on the subject .
This review focuses on the construction of the foundation pit construction construction design around the current lack of safety awareness problem, a lot of excavation works on the basis of the accident , summarizes and analyzes the various forms and the main reason the accident , and several kind of safety evaluation methods to compare and choose, select a  
security evaluation methods with engineering examples be qualitative or quantitative analysis, and thus proposed to control and eliminate hazards corresponding measures to perfect the construction organization design .
Articles for construction design construction process accident rates were higher safety analysis and fault tree analysis were selected for excavation construction accident charged nursing agencies to analyze LEC method used in the construction process of the construction accident analysis . Fault tree analysis for the application of more and Excavation higher accident rates piles , diaphragm walls , and grading excavation three kinds of retaining structure is constructed to find safety hazard fault tree model, and each respectively a qualitative fault tree analysis, combined with the use of the results of qualitative analysis and process engineering for expert simulation before scoring, quantitative analysis of the results obtained .
In this paper the process of fault tree analysis to draw some conclusions , systematic risk sources according to the size of the basic events critical degree or minimum cut set probabilities to determine the size . Basic events critical degree greater, indicating the greater its harmfulness ; a minimal cut sets represent a failure mode , failure mode probability of occurrence of a large event is focused on the basic control of hazardous events .Through the minimal cut sets and critical degree of probability the result is the same, so long as the calculation of critical degree , you can identify which hazards are the weak link in the system , it can be a risk factor for the system to take measures to improve the system security, so that the design of construction organization more successful . There is a simultaneous minimal cut sets more, then Excavations system will increase the probability of an accident . Therefore considered as fully as possible and controlling risk factors for ensuring the safety of foundation pit is very important .This fault tree was created in the learning foundation pit engineering design principles, construction methods , according to the provisions of the relevant national norms , combined with numerous pit engineering accident on instance data based on the analysis done , this paper established three branches fault tree retaining structure has better adaptability to other works in the safety evaluation generally can be referenced directly . Excavation for a strong personality , when the need to establish itself on the specific characteristics of the fault tree model, this paper established fault tree model can be used as its reference in this article to be improved on the basis of the model , can save a lot of work .In this paper, the proposed excavation engineering fault tree model to recognize the actual project security risks with a more positive meaning to be worthy of further study and application. 大型地基安全施工组织设计+文献综述(2):http://www.751com.cn/gongcheng/lunwen_8196.html