1 Importance of investment control in railway engineering design stage
Investment control is the control element of project construction, which runs through the whole process of project construction. According to the existing research, the influence of different construction stages on project investment is as follows: the decision-making stage of project proposal and feasibility study is more than 75%; The initial design stage is (35 ~ 75)%; The construction drawing design stage is (5 ~ 35)%; The construction stage is (5 ~ 25)%. The design stage is the premise of controlling the investment of the whole project, and the importance of the design stage to the investment control of the project is mainly reflected in: 1) Grasping the project cost structure through the design budget estimate, observing whether the "function and cost" of each part of the construction project match, promoting the rationality of the cost and improving the utilization rate of funds. 2) Through the design budget, master the general situation of project investment, strictly control all investment links, and improve the efficiency of investment control. 3) The combination of technology and economy not only ensures the engineering function, but also does not ignore the economic cost. Achieve the predetermined goal with the minimum investment and ensure the investment benefit.
2 cases demonstrate the objective law of railway engineering design stage
2. 1 case introduction
The railway construction project from Data Station to Machanghao, designed by Lanzhou Railway Design Institute Co., Ltd., is located in Erdos City, southwest Inner Mongolia, and passes through Dalat Banner under the jurisdiction of the northeast of the city. The total length of the main line is about 59km, and the bridge-tunnel ratio is about 26%. Main technical standards: single track, national railway grade II, limited slope of 6‰, minimum curve radius of general section 1200m. The total investment of the project is estimated to be 654.38+38 million yuan. Among them, the static investment is 65.438+26 billion yuan; The loan interest during the construction period is 60 million yuan; The purchase cost of locomotive and rolling stock is 60 million yuan; The working capital of the foundation is 03 million yuan; This project is invested and constructed by Hohhot Railway Bureau in consultation with Ordos Municipal Government and related enterprises, and a joint venture railway company is established to undertake the project construction and operation.
2.2 the complexity of engineering design
2.2. 1 Complex natural features determine the complexity of railway design. From west to east, the landforms along the railway project from Data Station to Machanghao can be divided into three landforms: alluvial plain area of the Yellow River, desert area and hilly area. The surrounding rock of the tunnel is poor, the soil surrounding rock is poor, and the buried depth is shallow, crossing Baomao Expressway. In the design stage, appropriate technical standards should be selected according to the corresponding geological conditions, all kinds of protection work should be done in advance, and the detection and prediction of tunnel seismic fault zone should be strengthened; The entrance and exit sections and the tunnel body should be well supported to prevent collapse and roof fall, and ventilation measures should be taken.
2.2.2 The complex railway technical standard system determines the complexity of design, the continuous development of social economy and the diversification of railway demand. Railway construction has formed three relatively independent and interrelated technical standard systems: high-speed railway passenger and freight mixed transportation, passenger dedicated line and freight railway. Data to Machanghao Railway belongs to freight railway. Subgrade engineering design shall strictly follow the technical standard of freight railway: 1). Part of the subgrade of this line crosses semi-fixed and fixed sand, and the main engineering type is aeolian sand subgrade. The protection of aeolian sand subgrade adopts the treatment method of combining ontology protection with plane protection; 2) The line crosses silty sand, silty sand and other strata, and there is soft foundation at the same time. The foundation treatment project adopts composite foundation treatment methods such as digging and filling, laying geomembrane, dynamic compaction, geogrid and berm, and sand piles when necessary.
2.2.3 There are many professional projects and complicated technical interfaces. Railway design covers more than 20 professional projects such as civil engineering and electromechanical equipment. In the design, it is necessary to correctly solve the professional interface relationship according to the design concept of the system in order to achieve the best system design goal. For example, focus on interface management and sort out interface relationships; Formulate effective and feasible measures to ensure the accuracy and integrity of investment and avoid investment duplication and missing investment.
2.3 Railway construction projects have the characteristics of multi-stage pricing. According to the current railway construction procedures and management, the decision-making stage is mainly responsible for the preparation of "budgetary estimate and estimate" for investment, the design stage is mainly responsible for the preparation of "budgetary estimate and budget", the transaction stage is mainly responsible for the preparation of "tender estimate", and the implementation stage is mainly responsible for the preparation of "budget estimate for changing design, clearing budget estimate and final accounts for completion". The investment requirements of each stage are different, and their functions are different. For example, if the estimate in the feasibility study stage is approved, it will be the "legal limit" for project investment control; Final accounts for completion are the actual investment of the project. Therefore, based on the viewpoint of overall control, railway investment should take care of each other, complement each other, improve each other, deepen investment, and make it gradually real.
3 railway engineering design stage investment control measures
3. 1 Construction of design reserve system
Preliminary design and construction drawing design are two major stages of design, and each stage includes three design stages: early stage, middle stage and late stage. In the early stage of design, it is the primary link to ensure the design quality to undertake on-site investigation and technical reserve tasks and collect first-hand information for the preliminary technical design in the middle and late stage. In order to strengthen the design work in the early stage of the project, before the project starts, the railway survey and design institute is entrusted to carry out on-the-spot investigation, build a "design reserve system", reserve the data of "geology, environment and route direction" along the project, and leave enough time for the design demonstration and scheme comparison in the middle and late stage to ensure that the scheme is reasonable and meets the technical standards.
3.2 Implement the responsibility system for survey and design units and introduce the design supervision system.
Relevant research shows that the impact of survey and design on project investment control is (35 ~ 75)%. After signing the contract with the design unit, the construction company requires the design unit to implement the "technical and economic" responsibility system and "post" responsibility system for professional designers according to the professional support, formulate the reward and punishment assessment system, and implement the total investment estimated by the feasibility study to each major. Clearly implement the design technical coordination between "design general contractor" and "subcontractor". In addition, the design supervision system is introduced, the supervision of design quality is strengthened, and supervision institutions are established to supervise the "design scheme" and "project cost" in each stage of design. Improve the design quality in the design stage of railway engineering, strictly control the investment limit and insist on reasonable pricing, that is, according to the "topography, geology, landform, construction method and time limit requirements" of railway engineering, formulate a scientific, reasonable and practical pre-tender estimate to reduce investment risks.
3.3 Implementation design
Bidding and design scheme campaign measures use the market competition mechanism to initiate the design bidding of construction projects and select the best design scheme and unit. If the design unit wants to win the bid, the premise is to make a detailed analysis and comparison of the "scale, equipment selection, technical standards, functional scheme and investment control" of the construction project. The bidding scheme must be "economic and reasonable, technologically advanced", put the investment effect of the project first, and participate in the election with an economic and reasonable design scheme. The construction unit uses "value engineering" to make technical and economic analysis and comparison of campaign design schemes, and selects a "technical selection, economic and reasonable" design scheme that can meet the technical and functional requirements and reduce investment. With the implementation of design bidding and design scheme competition, the conditions of railway horizontal and vertical sections have been optimized, the length of which is 6.626 km shorter than that of 65.626 km in the feasibility study design, and the special Gao Qiao has been adjusted from 1 148m to1/09m, which has achieved remarkable technical and economic benefits.
3.4 Adopt quota design
Using quota design to control project investment quota is an important measure to control investment. Quota design refers to the "construction drawing design of investment estimation control and total budget control" based on the approved feasibility study report and preliminary design. In addition, on the basis of ensuring the use function of each major, the investment control design is carried out with the allocated investment limit to prevent unreasonable changes of unit projects and sub-projects and ensure that the total investment limit is not exceeded. Practice shows that investment allocation and engineering quantity control are effective means to realize "quota design", which embodies the scientific determination of design "scale, standard and principle" and the scientific acquisition of budget information. Through the hierarchical quota design, the investment quota is controlled scientifically, and at the same time, the standards and elements such as "scale and standard", "budget index" and "engineering quantity" are controlled. See figure 1 for the operation flow of investment control.
3.5 Using the principle of value engineering to optimize the design scheme
Based on the principle of value engineering, make up the deficiency of quota design in practical application, allocate the total value of design quota reasonably, and then determine the cost proportion of its functional objectives according to the functions of each component of the project, and then adjust it with reference to the experience data of similar projects, so as to eliminate the influence of maintenance cost on functional evaluation after the completion of analysis objectives and reflect the initiative of quota design. In the practice of newly-built Bao-Shen railway project, the ways to improve the product value are: 1) While improving the engineering function, reduce the investment quota. 2) Reduce the investment quota on the premise of keeping the engineering function unchanged. For example, by optimizing subgrade engineering, reduce the infiltration soil for foundation treatment12.16×104m3, cancel the gravel pile for foundation treatment11.69×104m, and reduce the dynamic compaction14m. 3) Under the premise of constant project investment, improve the engineering function. 4) Under the premise of keeping the main functions of the project unchanged and slightly reducing the secondary functions, the investment will be greatly reduced. For example, through optimization, the drainage, roads and fences of the station are reduced, and the cost is reduced by 6,692,200 yuan. 5) On the premise of slightly increasing the engineering investment, the engineering function will be greatly improved.
3.6 Strengthen design consultation.
Design consultation is the key to optimize "preliminary design" and "construction drawing design". After determining the design unit, entrust a professional consulting unit to review and optimize the "preliminary design" and "construction drawing design"; When designing, we should check the process of "feasibility study report evaluation agency, preliminary design consulting agency and construction drawing audit agency" at different levels, plug the loopholes in the wall, correct the mistakes, coordinate and unify the "professional design" before the station and the "engineering economy" after the station, and achieve the accuracy of "quantity quota". The design consultation flow chart is shown in Figure 2.
3.7 Strengthen the management review of scheme budget and construction drawing budget preparation.
In order to prevent the budget estimate from being inconsistent with the design and construction, and improve the quality of the budget estimate, the following points must be achieved: 1) The budget estimate preparer and the designer should communicate with each other, and the budget estimate preparer should ask the designer in detail about the ambiguities; 2) Improve the professional quality, self-quality and sense of responsibility of budget preparers; 3) Carefully review the preliminary design budget and effectively control the project cost. Construction drawing budget is very important for determining contract price, signing construction contract and project settlement, which directly affects investment control. In addition to the design unit, the construction unit and the budget review agency need to strengthen the review of the preliminary design budget to ensure the rationality and authenticity of the budget and avoid losses.
4 conclusion
With the rapid expansion of railway construction scale, a large amount of construction funds are needed, and the rationality and effectiveness of project investment control has become an important topic in railway construction management. In addition, it is very important to implement investment control in the design stage because of the unique complex and objective laws of investment control in railway engineering construction. At present, the research on investment control of railway projects from "decision-making, design, contracting, construction and completion" will continue to deepen, hoping to enter the development track of "systematization, legalization and intensification" management in the near future. Only by constantly summing up the past experience, facing up to the existing problems and looking for improved methods can the railway construction project management reach a new level, thus ensuring the timely realization of investment benefits.
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