This paper analyzes the reasons for the high cost of highway engineering in Shanxi Province, and points out that highway survey and design is an important link in the process of highway construction, which is of great significance to highway construction.
Quality and project investment play a controlling role. From the design point of view, this paper discusses the measures to reduce the cost of expressway engineering, so as to solve the problem of insufficient construction funds.
Keywords: expressway, design, project cost, reason
In recent years, with the full implementation of the national expressway network, expressways have been comprehensive.
Extending to mountainous and hilly areas, the average cost of expressways per kilometer exceeds 60 million yuan.
The problem of insufficient construction funds is particularly prominent in mountainous and hilly areas like Shanxi.
There are both objective and subjective reasons for the high cost of expressway projects in Shanxi Province.
Objective reasons mainly include:
1) Most of Shanxi Province is mountainous and hilly, with complicated gullies and numerous bridges and tunnels.
Large quantity;
2) There are many mined-out areas in coal mines, and the treatment cost is high;
3) The local road network is perfect, and there are many interchanges and overpass bridges;
4) The amount of cultivated land requisitioned by expressway is large, and the cost of land requisition is high;
5) Lack of local material resources and high unit price of sand and gravel materials.
Subjective reasons mainly include:
1) In order to start the project as soon as possible, the design department was not given a reasonable design cycle, or even
Design and construction at the same time, resulting in insufficient depth of survey and design and more;
2) The local planning changes rapidly, and there are more and more designs, which makes the engineering quantity increase continuously;
3) The bidding documents are not standardized, the bill of quantities is not comprehensive, and the contract terms are not comprehensive.
Tight, there are loopholes in management;
4) Designers have the idea of ensuring quality and ignoring cost.
Objective reasons are determined by natural conditions, which are basically inevitable, and
Subjective reasons can be overcome or reduced by human efforts and effective measures.
Highway survey and design is an important link in the process of highway construction and the soul of the project.
It plays a controlling role in highway construction quality and engineering investment. How to control expressway engineering
Cost and rational use of every penny must start with design.
The main measures to reduce the project cost in design are as follows:
1) route: change the backward design concept, deeply understand the connotation of the specification, and be flexible.
Deepen the depth of comparison and selection of route schemes with technical indicators. While meeting the highway function, keep
Under the condition that the existing road network is complete and the people are convenient to travel, the height of subgrade fill should be reasonably reduced.
Reduce debit and land occupation. Control the elevation to achieve the balance and total amount of subgrade earthwork filling and excavation.
At least it is the focus of mountain highway design, and the key of mountain highway design lies in horizontal and vertical.
Index value and balance. Flexible use of technical indicators is the starting point of design and protection.
Environment, the basis of saving investment. From the 1980s to the mid-1990s, high speed
Highway construction is mainly concentrated in plain areas. During this period, the guiding ideology of highway survey and design
Mainly based on the principle of "fast, safe and economical", it emphasizes the coordination of linear stretching and vertical and horizontal combination.
Reasonable, comfortable driving and good visual effect. One-sided emphasis on adopting high standards and indicators,
The subgrade of the completed expressway is generally high, which not only occupies too much precious land.
The resources and landscape effects are not ideal. At the beginning of 2 1 century, highway construction in plain areas was put forward.
The design principle of low embankment is to reduce the height of subgrade, and a large number of high embankments have been built in mountainous areas at the same time
Facing the unique and complicated natural conditions in mountainous areas, designers still use plains as expressways.
The design concept of this area emphasizes higher technical standards, and a large number of high-filled and deep-dug subgrade have appeared.
It not only destroyed the natural environment in this area, affected the highway landscape, but also induced a lot of land.
Quality disasters directly affect the normal operation of roads and increase the project cost.
2) Subgrade: Subgrade design should be the main and key component of the overall design.
Actively participate in the overall design and control the main factors affecting the cost from the source. As healthy as possible.
Embankment height in low plain and hilly areas, and reasonably determine high-filling and deep-digging roads in mountainous and hilly areas.
Base; The section form of subgrade should adapt to the terrain characteristics, and the whole subgrade should adapt to the plain area; mountain ridge
The separated subgrade in the area can make maximum use of the space resources of the line corridor, which should be strongly advocated in mountainous areas.
When designing the regional route, each direction should be designed separately, or the vehicles should be separated and staggered.
Tao; Slope design should be carried out under the principle of slope stability, and attention should be paid to dynamic design.
Planning and information construction; Side ditches are designed according to the drainage needs, according to the safety scouring and
Aesthetics requires setting protection types; Greening protection is to use the anti-scouring function after planting grass.
In pursuit of intuitive protection form, soil slope should advocate plant protection or no protection,
Natural bare excavation can be used for stable rock slopes; Soft soil foundation treatment should be from
Considering the harm of soft soil foundation to highway subgrade, within the allowable settlement range,
Try to use the time to meet the treatment requirements, do little or no underground work, and pay attention to
Settlement and stability observation, strengthen the dynamic design and information construction of soft foundation treatment;
Landslide prevention and control must be clear about the knowability and governability of landslide, so as to avoid or control landslide for the route.
Poe made a decision.
3) Bridges: Bridges are structures that span rivers, lakes, straits and valleys, that's right.
Ensuring smooth road network plays an irreplaceable role and is a key section in road network construction.
Point. The cost of bridge is much higher than that of subgrade engineering, especially the expressway developed to mountainous areas.
After that, a large number of bridge and culvert structures appeared, so it is very urgent to effectively control the investment scale.
The bridge location is an important control point of route layout, and the bridge location layout should not be excessive.
Emphasize the principle of "the choice of bridge location should obey the route" and try to avoid a large number of high piers.
Long-span skew bridge with curved slope to reduce the scale and technical difficulty of bridge engineering. Bridge type scheme selection
In order to adhere to the design principle of "safety, applicability, economy, beauty and convenience for construction and maintenance", we should
Multi-scheme comparison and selection. The calculation method used in structural design should be reliable, and the size selection should be important.
Reasonable, the selection of steel bar diameter and the arrangement of spacing should fully meet the requirements of structural stress.
Pay attention to the design of construction scheme and the combination of bridge scheme and construction scheme to avoid problems in construction.
Unreasonable scheme selection leads to the increase of project cost.
4) Tunnel: Highway tunnel is different from ground engineering and is greatly influenced by topographic and geological conditions.
Tunnel design should grasp the key points and working depth of geological exploration in each stage, seek advantages and avoid disadvantages,
Accurate classification of surrounding rocks, integrating geological advance prediction and monitoring and measurement of surrounding rocks.
This process is included in the design document. Combined with topography, geological conditions, external wiring and structure
Layout, follow the principle of "early entry and late exit", and reasonably choose the location and design of the portal.
It should be safe, concise and practical, with less slope brushing and less damage to the natural environment of the mouth of the cave. Tunnel lining crossing
Section and structural form should be reasonable and effective to adapt to construction conditions and meet durability requirements.
Composite lining structure is generally adopted, and necessary auxiliary construction measures are taken as far as possible.
Standardized pre-design Tunnel drainage design should be based on scheme design, material selection and construction.
Overall consideration of maintenance, local conditions, comprehensive management, and emphasis on maintainability.
When soil and water resources may be lost, or the ground structure may be destroyed, "plugging" should be adopted.
Prioritize and limit emissions. " The electromechanical design of tunnel should be combined with the actual traffic conditions.
Analysis, mechanical and electrical facilities should be moderate in scale, pay attention to safety and energy saving, and be planned and divided.
Period of implementation, and gradually improve.
5) Interchange: Interchange is a large structure, and its cost is in general construction.
The price accounts for a considerable proportion, especially the hub interchange, which has a larger proportion and a moderate design.
It is of great significance for saving investment. Interworking design should attach importance to road network investigation and master road network regulations.
Planning to avoid unreasonable interchange schemes caused by changes in road network planning. set up
Attention should be paid to the comprehensive comparison and selection of route scheme and interchange scheme, and the main line, ramp,
Intersection between roads. Try to adopt small-scale and low-cost "slimming".
Interchange schemes, especially those in mountainous areas, have complex geological conditions and different setting costs and locations.
There is a big difference, so we should strengthen the comparison and selection of interoperability schemes. Under the condition of meeting the traffic capacity,
The ramp design speed should be determined according to the traffic volume, and should not be too high to reduce the ramp scale.
References:
[1] Highway Department of the Ministry of Communications. Guide to highway design to reduce costs [M]. Beijing: People's Communication.
Children's Press, 2005.
[2] Highway Department of the Ministry of Communications. Guide to New Concept Highway Design [M]. Beijing: People's Transportation
Press, 2005.
[3] Chen Gensheng. Investment control of engineering project design [J]. Shanxi Architecture, 2007,33
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