Among them, the direct impact on the development of precast buildings is the high cost.

1.1 influencing factors of component procurement cost in the procurement process of precast components, the change of component price, the change of component market supply and demand, the selection of suppliers, as well as the component procurement mode and component supply time will lead to the change of component procurement cost.

This paper uses entropy weight matter-element extension model to evaluate the cost influencing factors, which is objective and reasonable.

The influence of subjective factors on the weight of each index should be avoided as far as possible to make the evaluation results more reliable.

In 2019, the new construction of precast buildings in China will reach 420 million m2, driving social investment of nearly 3 trillion yuan.

2.1 entropy weight method entropy represents the disorder degree of the system, and entropy weight represents the amount of useful information carried by each index.

1 Analysis of influencing factors of general contracting cost of precast building construction in order to identify the influencing factors of general contracting cost of precast building construction, learn from previous research results, identify the cost influencing factors through literature induction, and establish influencing factor indicators in component procurement, component transportation and construction installation.

However, there are still many problems in the development of precast buildings in China, such as high cost, immature precast technology, lack of standards and specifications and so on.

In matter-element analysis, let matter-element m, the feature of matter-element m is C, and the corresponding eigenvalue is x, which is called the three elements of matter-element R.

1.3 factors affecting the cost of component construction and installation include the secondary handling cost of components and the loss of components caused by handling, component storage and maintenance, whether the hoisting machinery and equipment are appropriate and the efficiency of hoisting, the cooperation level between types of work, the technical level of installers, project management level, construction sequence and process, construction progress, construction quality and project safety, etc, Will cause changes in component construction and installation costs.

(2) The entropy Di of the influencing factors of precast construction cost is: 2.2 matter-element extension model.

1.4 list of factors affecting the cost of precast construction according to the above analysis, the list of factors affecting the general contracting cost of precast construction is shown in Table 1.

In recent years, information entropy theory has been preliminarily applied to the fields of engineering structure reliability analysis, financial risk analysis, surrounding rock stability analysis and engineering project management.

In this paper, the entropy weight method is used to determine the specific formula of index weight as follows: (1) normalize the evaluation index matrix: where Xij is the scoring of J indexes by the ith individual participating in the evaluation, I = 1,2,3…, m, M is the number of people evaluated, j is the influencing factor index, and xmax and xmin are the highest and lowest scores of the index score.

From 2016 to 2019, the new construction area of precast buildings showed a rapid growth momentum.

The matter-element extension of entropy weight is used to determine the index weight.

From the perspective of general construction contracting, this paper uses entropy weight matter-element extension to evaluate the influencing factors of precast construction cost from three aspects: component procurement, component transportation and construction and installation.

The greater the entropy weight, the more useful information it carries, the greater the role of the index in the comprehensive evaluation, and the higher the index weight, and vice versa.

Shuttering Magnet

According to the setting of matter-element, in the matter-element system, matter-element combines things, characteristics and quantitative value.

In the past, most scholars analyzed and studied the factors affecting the cost of precast buildings from the whole process or construction process of precast buildings.

1.2 factors affecting the transportation cost of components in the transportation process of precast components, the transportation distance between the component factory and the construction site, the type of vehicle selected in the transportation process and the selection of transportation route.

When dealing with problems, we should consider both quantity and characteristics.

Matter-element extension model is a direct problem-oriented mathematical method.

In this paper, the influencing factors of precast construction cost are the matter-element we discuss..

Since the general office of the State Council issued the guidance on vigorously developing precast buildings in 2016, the industrialization of new buildings represented by precast buildings has been promoted rapidly, and the construction level and quality of industrialized buildings have been significantly improved.

In the evaluation process of multi-objective factors, the weight of evaluation indicators occupies an important part.

That is, r = (m, C, x).

In addition, the transportation protection and transportation loading efficiency of components will cause changes in the transportation cost of components.

The establishment of entropy weight matter-element extension model using analytic hierarchy process, interpretation structure model and other evaluation methods inevitably has subjective problems.

In the constructed evaluation index system, it is generally an objective level index.

Abstract: from the perspective of general construction contracting, this paper selects 20 influencing factors of precast construction cost from three aspects: component procurement, component transportation and construction and installation, analyzes the influencing factors by entropy weight matter-element extension evaluation method, and determines the component supply relationship, component procurement mode, transportation distance, component transportation protection, vehicle type, secondary handling The cooperation level between types of work, project management level and construction quality are the factors that affect the cost of precast construction, and put forward relevant countermeasures and suggestions for the above influencing factors.