Fault tree safety assessment work is generally quite complicated, so you want it widely used in various Excavation safety evaluation , but also takes some effort . In the fault tree method is the most important and the most difficult is how to determine the probability of occurrence of the basic events . Excavation is currently difficult to gather information on the accident , many aspects of the foundation pit accident data recording exhaustive , more big tree pit accident safety evaluation of difficulty ; and because of the particularity of excavation engineering , basic probability of the event is due when change from place to place , this is only simulated expert scoring approach to identify the basic event probabilities so for basic event probability method to determine the value of research to be continued .Most of the current excavation works focus only on monitoring the work itself, on-site construction environment , natural conditions, little data is recorded , is not easy to summarize and analyze . Therefore, in order to promote the safety assessment work carried out to improve the safety assessment fault tree accuracy of the results must be gradually standardized monitoring , engineering practice to accumulate more data storage accident data , the establishment of a database failure rate .
This foundation Construction Construction Accident safety evaluation is done through LEC method , the operating conditions of risk assessment method that people in some potentially dangerous operating environment for the degree of risk operations , the method is simple , the degree of risk level pided more clearly, eye-catching. However, because it is mainly based on three factors empirically determined fraction of the value of the degree of risk level and delineated , it has some limitations . And it is a job for local evaluation , it is not universally applicable . Therefore, this paper briefly its construction accident analysis .
KeyWords：Construction organization ; safety evaluation ; fault tree ; LEC
目 录
1绪论 1
1.1选题科学依据 1
1.2 课题的目的及其意义 1
1.2.1课题研究的目的 1
1.2.2课题研究的意义 2
1.3 本文的主要研究内容 2
2 工程概况 4
2.1 地下工程设计概况 4
2.2 地下室逆作区支护结构设计概况 4
2.3 工程条件 4
2.3.1 工程环境条件 4
2.3.2 工程地质水文条件 5
2.4 工程特点 5
3 主要施工方法 6
3.1地下连续墙施工 6
3.1.1 施工准备 6
3.1.2施工流程 6
3.1.3施工方法 7
3.2 基坑内土体加固工程施工 8
3.2.1 SMW工法水泥土搅拌桩施工流程 8
3.2.2施工方法 8
3.3新增立柱桩及立柱施工 9
3.3.1施工工艺流程 9
3.4 土方工程施工 9
3.4.1第一阶段的土方开挖和平面布置 10
3.4.2第二三阶段的土方开挖 10
3.4.3第四阶段土方开挖 10
3.4.4第五阶段土方开挖 11
4深基坑危险有害因素辨识 12
4.1事故类型 12
4.2危险源辨识 12
5 安全评价分析 15
5.1常用安全评价方法比较及评价方法选用 15
5.1.1常用安全评价方法比较 15
5.1.2安全分析方法的选择 17
5.1.3选用安全评价方法的介绍（FTA、LEC） 17 大型地基安全施工组织设计+文献综述(3):http://www.751com.cn/gongcheng/lunwen_8196.html