Study on the Evaluation and Countermeasures of Green Construction of Construction Projects

. In recent years, with the advancement of urbanization in China, the management idea of infiltration of green construction in the construction process can not meet the needs of the industry development. Comprehensive and systematic green construction planning, development and application of green construction technology will be a new driving force to promote the sustainable development of the construction industry. Construction scheme and process standardization, site facilities standardization, construction measures industrialization, site environment garden, site management information is the main focus of our action. Evaluate the construction project of green construction, is not only beneficial to the promotion of green construction, can timely find the deviation appeared in the process of project implementation, guarantee the project of the construction of the economic benefits, social benefits and ecological benefits, will also be able to provide reference and guidance significance for other similar project, improve the level of future overall implementation of the construction project and environmental benefits.


Construction principles of green construction evaluation index system
The green construction evaluation of construction projects needs to collect a lot of data and information, and the collected information is integrated and processed, and finally a comprehensive analysis result is obtained. Therefore, we should not only follow the scientific principle of the green construction evaluation index system, but also establish the green construction evaluation system scientifically and orderly on the basis of the existing principles. The principles of constructing the evaluation index system are as follows:

Systemic
The index factors of the green construction evaluation index system of construction projects should be considered from all aspects, and the evaluation index factors should be very representative. The objective, fair and comprehensive scientific evaluation of green construction should be carried out, so as to lay a solid theoretical foundation for the construction of a sustainable, stable and efficient green construction evaluation model.

Dynamic
The whole life cycle of a construction project is a dynamic process. Based on the basic theoretical principles and dynamic principles of green construction evaluation, the green construction of a project is evaluated by considering relevant indicators with dynamic and temporal characteristics.

Significance
The selection of evaluation indicators should ensure the irreplaceability and particularity of the indicators in the project. Since there are many evaluation indicators of the project, the factors that have a great influence on the green construction of the construction project should be selected as the main evaluation indicators in the selection process.

Operability
There are many indicators that affect the green construction of construction projects, including quantifiable and unquantifiable indicators. In order to ensure the objectivity and fairness of the evaluation results, the project index system should be determined based on the principle of operation.

Construction of evaluation index system
At present, the research on green construction evaluation of construction projects has organically integrated the development of construction enterprises and environmental protection, and finally formed a situation of comprehensive and coordinated development of nature and society. Green construction is closely related to the rational utilization of resources, the management of construction enterprises, the implementation of construction technology, the investment of construction costs and the impact on the environment in the whole project implementation process. If only one or several factors are taken into consideration in the evaluation process of green construction of construction projects, it may lead to the phenomenon that the actual situation of the project cannot be fully reflected due to the single selection of indicators, which is also one of the most obvious drawbacks in the evaluation index system at this stage. This paper takes this as the reference basis, and makes innovative evaluation on the rational utilization of resources, management of construction enterprises, implementation of construction technology, investment of construction costs and impact on the environment as the main content. The specific evaluation index can be selected according to the experience of similar project evaluation in the past, or the qualitative index can be quantified by some mathematical methods. The experience selection method mainly summarizes the influential factors by the professionals in the field according to the individual in the implementation process of the actual project, and makes a finer screening of the obtained factors. The disadvantages of this method are mainly that the degree of subjective influence is large, and the objectivity of the factors is low. When using principal component analysis method and other relevant mathematical methods to screen indicators, it mainly quantifies the importance of index factors to reduce the influence of people's subjective factors on the

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Volume 25 (2022) selection of indicators, but this method lacks the subjective analysis of logical relations among complex factors. In this article, therefore, the selection of evaluation index system in use in the process of Delphi method, this method first by the results of expert opinion after sorting, inducing and summarizing the results obtained will be feedback to the expert, so repeatedly, until the final experts agree the results, the method avoids the single by the empirical method and research method of index selection of disadvantage, the implementation of the specific process as shown in figure 1.
Based on the principles of green construction evaluation index system construction and Delphi method, this paper constructs the evaluation index system, and finally divides the evaluation index factors of green construction into three levels for research and analysis. Firstly, the target layer is the green construction evaluation of the construction project. Secondly, the criterion layer includes the rational utilization of resources, the management of construction enterprises, the implementation of construction technology, the investment of construction costs and the impact on the environment. Finally, the second-level indicator layer is divided into 20 specific indicator factors according to the actual situation of the five criterion layers, including the rational utilization of water resources and building materials in the rational utilization of resources, as shown in Table 1.

Construction of green construction evaluation model for construction project
In this study, the study of green construction evaluation of construction projects adopts AHP-fuzzy analysis method, combining quantitative and qualitative analysis, to solve the related problems of green construction evaluation of construction projects.

The characteristics of AHP-Fuzzy comprehensive evaluation method
Analytic hierarchy Process (AHP) is a practical evaluation method of multi-criteria decision making. Because it can make various factors related to complex problems more organized and clearer,

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Volume 25 (2022) 834 it is favored by researchers. The fuzzy comprehensive evaluation method makes a reasonable classification of the quality of each index factor. In the best way to solve the fuzzy, difficult to quantitative analysis of the problem. The effective combination of the two methods makes the analysis result convincing.

Construction of evaluation model based on AHP-Fuzzy
①Construct judgment matrix To determine the weight, several experts with relevant professional knowledge background will be invited to give scores, and the indicators to be evaluated will be compared pairwise, and 1-9 scale method will be adopted. The i and j elements are equally important 3 I is slightly more important than j 5 I is obviously more important than j 7 I is more important than j 9 I is more important than j 2、4、6、8 Between the two values ②The weight of each factor index was calculated and the consistency was checked , When the value of CR is less than 0.1, it indicates that the judgment matrix meets the consistency test standard and obtains that it has consistency. ③Make a comprehensive evaluation The words V ={good, better, medium, average, poor} of the evaluation object are established, namely, the evaluation level, and each level can correspond to a fuzzy subset.The set of assigned comments is V={95,85,75,65,55}.
The established comment set is used to evaluate a single factor by experts, and the fuzzy evaluation matrix R of each factor in the index layer is obtained. The judgment matrix of each evaluation factor index Cij can be expressed as: , and the evaluation result BRi of a single index is obtained.
Through the conversion of the whole evaluation result and weight, the formula can be obtained Using the data T obtained in the previous step and the corresponding score of the comment set score to calculate T V T Score × = .

Evaluation analysis of construction project hotel construction based on fuzzy comprehensive evaluation method 4.1 The establishment of fuzzy relation matrix
The survey objects of this paper include government staff, scholars in universities, staff of digital communication companies, and the public, etc. A total of 350 questionnaires were sent out, and 280 valid questionnaires were obtained. After sorting out the scores of the importance of each index, the following judgment matrix can be obtained after multiple selection.  Through the calculation of relevant calculation formulas, it can be obtained that all indexes have passed the consistency test. The weight of each factor index is summarized in Table 3 as follows.
In this paper, a total of 300 questionnaires were sent out and 264 valid questionnaires were obtained. The membership results were summarized in the following table.

Analysis of evaluation results
According to the result of membership degree of each index above, it can be calculated by fuzzy comprehensive evaluation formula R W T × = .
BCP Business & Management According to the calculation, the green construction evaluation value of the construction project is 75.89, which is above the medium level, indicating that there is still some room for improvement in the green construction of the construction project. At the same time, the score of rational utilization of resources is 70.915 points, the score of management of construction enterprises is 79.389 points, the score of implementations of construction technology is 74.068 points, the score of input of construction cost is 71.181 points, and the score of impact on environment is 70.880 points.

Establish resource conservation standards
Material saving and material resource utilization: reasonably arrange material entry plan and production and processing control, reduce material loss rate, and actively promote and apply the "Four New" plan; Achieve steel loss rate of less than 2.5%; The loss rate of concrete is less than 1.5%, the average turnover of traditional formwork is more than 6 times, and the turnover rate of tool-type standardized equipment is more than 80%. Water-saving and water resources utilization: the allocation ratio of water-saving appliances for domestic use shall reach 90%, and the water consumption per ten thousand yuan of output value shall be controlled within 6t; Land saving and construction land protection: BIM5D technology is used for layout, reasonable optimization of temporary land area, and full use of the original road, site, etc.

Prepare the green construction plan
Before the enterprise organizes the green construction, that is, the organization prepares the project green construction plan, the construction plan has made the specific description to each work. Green construction plan preparation and construction organization design preparation synchronization, around the "four sections and one environmental protection" to develop green construction measures, at the same time, the application of new technology, new materials were refined.

Strengthen environmental protection measures
Sound dust control measures, such as: commercial concrete and ready-mixed mortar on site, minimize dust. To prevent water pollution, such as: the construction site sewage discharge to meet the national standard "sewage comprehensive discharge standard" requirements. Prevent construction noise pollution, such as: the site noise emission shall not exceed the national standard "construction site boundary noise limit" (GB12523-2011) provisions. Limit light pollution measures, such as: during night construction, reasonable adjustment of light irradiation direction, ensure that the site construction surface has enough light conditions, reduce the interference to the surrounding residents.

Strengthen green construction management
Establish and improve the green construction management system. Set up a green construction leading group with the project manager as the first responsible person and the project management personnel as members. Clear green construction management goal: fully embodies the "green construction" concept, adhere to the office courtyard, overlay facilities standardization, standardization site layout, construction scientific management, work out a clear regularization of the "five" standard, to protect the environment of production site and the surrounding environmental protection, prevent pollution of the environment, beautify the construction environment, saving the resources available.