Civil Engineering Construction Time Schdule Risk Analysis

The course of civil engineering projects is in progrese in complex natural and social environment, when in put process into practice is bound to accept risk factor effect surely.but the subject who is engaged in the project activity sometimes lack of awareness or do not have enough forces to control the risk, resulting in the time shcedule and the results are often contrary to the people's expectations, the disturbing factors appearinge certainty have also led to the high probability. To prevent and reduce such losses, the projects must be carried out effective risk management, time schedule of the project risk management is an important risk management, the article firstly recognizes the risk factors, and then analyzes the effect of these uncertain factors on the time schedule.Based on much reference and investigation, take underneath civil engineering embankment reinforcement projiect of WuHan and GuangZhou passenger line No.1 bid and No. 2 management lot as example, after distinguished and analysed the project risk factor,compose work as follows:①Based on simulated analysis of Monte Carlo and relevance theory of Monte Carlo and PERT, appraised and simulated analysed the uncertain lower condition time limit for a project.Aimed at hypothesis and calculation process of classical PERT theory, have analysed the defect there existing in it, and brought forward the concrete measure solving the problem, had been in progress from probability theory , number reason statistics angle, had defined and ascertained the key circuit again. Made use of emulation technology, seek the leading factor circuit and the key circuit, had simulated analysis analysed every circuit movly, based on a characteristic of circuit influences each other in PERT net, seek rational method, had revised completed probability in PERT theory net, and borrow computer, simulate and monitor the time limit for a project scatters of PERT net synchronously in method of MC.Get distributes law of the time limit for a project and it's completed probability synchronously.②Used function approximation function of BP neural network, had analysed and forecasted the time limit for a project deviation modulus in transverse direction angle from factor nerve basic, constructed progress risk prediction model of the BP network, provided a sciensic basis for managers for the initiatived controlling and dynamic controlling(3)Consider the various random factor effect effect in projects environmental,established a random learning curve model, scientifically explain and predict the fluctuations of the state of ergonomics;④Based on analysis to working procedure matrix, incidence matrix and power matrix of double code number network chart, proposed one kind of simple matrix algorithm about line inquiries and it's value solution. Produced the understands thoroughly, finally unified the example to confirm this algorithm simple and accuracy;⑤Firstly proposed the theory of generalized cost, brings the time, the cost and the quality into line with the cost category, and constructed integrated optimization model of Time, cost and quality based on the theory, with practical examples, the theory is proved feasible, science and economical.