Common knowledge points of Highway Engineering in 22 for the second-level constructor's exam: construction safety risk assessment of highway engineering projects

1. Construction safety risk assessment of highway cutting high slope engineering

The construction safety risk assessment of highway cutting high slope engineering is divided into two stages: overall risk assessment and special risk assessment, and generally adopts expert investigation assessment method and index system method.

1. Overall risk assessment. Taking the whole cutting engineering of expressway as the evaluation object, the overall risk assessment conclusion should be used as the basis for compiling the construction organization design of cutting slope engineering.

2. Special risk assessment. On the basis of overall risk assessment, the cutting section with high risk level (Grade III) and above is taken as the assessment unit, and the construction activities are taken as the assessment object. Special risk assessment can be divided into pre-construction special assessment and construction process special assessment. The conclusion of special risk assessment should be used as the basis for compiling or perfecting special construction scheme.

II. Safety risk assessment of highway bridge and tunnel construction

(I) Assessment scope

1. Bridge engineering

(1) Stone arch bridge with multi-span or span greater than 4m, reinforced concrete arch bridge with span greater than or equal to 15m, steel box arch bridge with span greater than or equal to 35m, steel truss and concrete filled steel tube arch bridge;

(2) beam bridges with spans greater than or equal to 14m, cable-stayed bridges with spans greater than 4m and suspension bridges with spans greater than 1m;

(3) Bridge works with pier height or clearance greater than 1m;

(4) Extra-large bridges and bridge projects with new materials, new structures, new processes and new technologies;

(5) Demolition or reinforcement works of special bridges or bridges with special structures;

(6) Other bridge projects with complex construction environment and complex construction technology.

2. Tunnel engineering

(1) Tunnel engineering with complex engineering geological or hydrogeological conditions, such as crossing high geostress areas, karst development areas, regional geological structures, coal measures strata and mined-out areas, and tunnel engineering in loess areas, underwater or submarine;

(2) Tunnel works with complicated structures such as shallow burial, unsymmetrical pressure, long span and changing cross section;

(3) Tunnel projects with a length of 3m or more, tunnel projects with continuous length of VI and V class surrounding rocks exceeding 5m or with total length accounting for 3% or more of the total tunnel length;

(4) multi-arch tunnel and small clear distance tunnel project;

(5) Tunnel engineering with new technology, new materials, new equipment and new technology;

(6) tunnel reconstruction and expansion project;

(7) Other tunnel projects with complicated construction environment and complicated construction technology.

(II) Assessment Methods

The safety risk assessment of highway bridge and tunnel construction is divided into general risk assessment and special risk assessment.

(1) Overall risk assessment. Before the bridge or tunnel project starts, according to the geological environment conditions, construction scale, structural characteristics and other risk environment and risk factors of the bridge or tunnel project, the overall safety risk during the construction of the bridge or tunnel project is estimated, and the safety risk level under static conditions is determined.

(2) Special risk assessment. When the overall risk assessment level of a bridge or tunnel project reaches Grade III (high risk) or above, the high-risk construction activities (or construction sections) are taken as the assessment objects, and the risk sources are surveyed according to their operational risk characteristics and similar engineering accidents, and the major risk sources are quantitatively estimated, and the corresponding risk control measures are put forward.

(III) Assessment Steps

The safety risk assessment of highway bridge and tunnel construction includes making assessment plans, selecting assessment methods, conducting risk analysis, conducting risk assessment, determining risk levels, proposing measures and suggestions, and compiling assessment reports.

Common knowledge points of Highway Engineering in 22, the second-level constructor's exam: relevant provisions on credit information management of highway construction

1. Measures for credit information management of highway construction market

1. Credit information of highway construction market includes basic information of highway construction business units, good behavior information of commendation and reward, bad behavior information and credit evaluation information.

2. The publication period of basic information of employees is long-term;

3. The time limit for publishing the information of good behavior and bad behavior of commendation and reward is 2 years, and the time limit for publishing the information of credit evaluation is 1 year. After the expiration, the system will automatically release the information and turn it into system file information. Bad behavior information before the expiration of the administrative penalty period will be extended to the expiration of the administrative penalty period. The above-mentioned time limits are calculated from the date when the corresponding behavior is identified or the corresponding decision is made.

2. Rules for credit evaluation of highway construction enterprises

1. Regular evaluation is carried out once a year to evaluate the market behavior of highway construction enterprises in the previous year (from January 1 to December 31).

2. The evaluation content consists of bidding behavior, performance behavior and other behaviors of highway construction enterprises. The evaluation unit of bidding behavior is single bidding of highway construction enterprises, and the evaluation unit of performance behavior is single construction contract section.

3. The initial score of bidding behavior and performance behavior is 1 points, and the cumulative deduction system is implemented. Among them, the bidding behavior accounts for 2%, and the performance behavior accounts for 8%. If there are other behaviors, it will be deducted from the total score of enterprise credit evaluation.

4. The tenderer is responsible for evaluating the bidding behavior of highway construction enterprises, the project legal person is responsible for evaluating the performance behavior, and the transportation authorities of the corresponding local people's governments are responsible for evaluating other behaviors.

5. The credit rating of highway construction enterprises is divided into five grades: AA.A.B.C.D The corresponding enterprise rating X of each credit rating is:

AA: 95 points ≤X≤1 points, with good credit;

grade a: 85 ≤ x < 95, with good credit;

grade b: 75 ≤ x < 85, with average credit;

grade c: 6 points ≤ x < 75 points, with poor credit;

grade d: x < 6, with poor credit.

6. An enterprise directly recognized as Grade D by a provincial transportation department is directly recognized as Grade C in the national comprehensive evaluation; The national comprehensive evaluation of highway construction enterprises that have been directly recognized as Grade D by two or more provincial transportation authorities and have been administratively punished by the State Council transportation authorities is directly classified as Grade D..

7. The credit upgrade of highway construction enterprises is implemented step by step, and only one grade can be upgraded every year, and it is not allowed to leapfrog.

8. The credit evaluation result of highway construction enterprises is valid for one year. If there is no credit evaluation result of highway construction enterprises in this province in the next year, its credit evaluation level in this province can be extended for one year. If there is no credit evaluation result in the province for more than 2 years, it shall be determined according to the first entry into the province, but it shall not be higher than the previous level of its original evaluation level in the province.

9. If the qualification of highway construction enterprises is upgraded, their credit rating will remain unchanged. If the enterprise is divided, the credit rating shall be determined according to the newly established enterprise, but it shall not be higher than the original rating. The merger of enterprises shall be determined according to the enterprise level with lower credit rating before the merger.

1. when a consortium participates in bidding, its credit rating shall be determined according to the lowest level of all parties to the consortium.

Part III Common knowledge points of Highway Engineering in 22 for the second-level builder's exam: management of the use of construction machinery and equipment in highway engineering

I. Production capacity and applicable conditions of construction machinery and equipment

1. Earthmoving machinery

(1) Bulldozers: mainly used for short-distance operations of 5 ~ 1m, such as subgrade construction, foundation pit excavation, site leveling and tree clearing.

(2) scraper: it is mainly used for medium-distance large-scale earthwork transfer projects. Scrapers are widely used in highway and railway construction. Scrapers should be constructed in grade I and II soil, and in case of grade III and IV soil, they should be loosened in advance. In terms of soil humidity, it is most suitable for construction in loose sand and clay with low humidity (water content below 25%), but it is not suitable for operation in dry silty sand and wet clay, and it is not suitable for operation in wet areas, swamps and rocky areas with high groundwater level.

(3) Loader: it is mainly used for engineering filling and excavation, and aggregate loading in asphalt and cement concrete yards.

(4) Excavators: mainly used for excavating and loading earthwork, including single bucket excavators and multi-bucket (wheel bucket) excavators, and all kinds of excavating machines are equipped with excavators.

(5) grader: it is mainly used for leveling subgrade and gravel pavement, site shaping and leveling in earthwork, and can also be used for trimming the cross section of subgrade, trimming the side slopes of embankment and cutting, and excavating side ditches and road grooves. In addition, it can also be used to mix stabilized soil or other pavement materials and paving materials on subgrade, trim and maintain dirt roads, loosen soil, backfill, remove weeds and snow, etc.

2. stonework machinery

(1) rock drilling machinery: there are rock drills and drills.

(2) Crushing machinery: According to structural features, it can be divided into jaw crusher, cone crusher, hammer crusher, impact crusher and roller crusher.

(3) There are two kinds of sand and gravel screening equipment: dry and wet.

3. Compaction machinery can be divided into three types according to the principle of compaction: static rolling machinery, vibration rolling machinery and tamping machinery.

4. Drilling equipment

(1) Spiral drilling machine: used for drilling and knotting of cast-in-place piles, deep mixing piles and precast concrete piles, which is suitable for geological conditions of soil;

(2) percussive drilling rig: it is used for bored pile construction, and has obvious advantages, especially under the geological conditions of pebbles and boulders;

(3) Rotary bucket drilling rig: suitable for all kinds of soil geological conditions except rock stratum.

(4) Hydraulic rotary drilling machine: it is suitable for all kinds of soil geological conditions except rock stratum, pebble and boulder geology, especially for municipal bridges and projects with limited site.

5. Tunnel construction machinery and equipment

(1) The rock drill is a mobile rock drill machine that supports the rock drill and completes the propulsion and displacement required for rock drilling operations. It is mainly used for large-section tunnel construction with good geological conditions and no temporary support.

(2) The boom tunnel boring machine, also known as the cantilever tunnel boring machine, is a tunnel boring machine integrating excavation, loading and unloading, and its production capacity is determined by the selected model and geological conditions.

(3) lining equipment is specially used for lining concrete and lining formwork equipment in tunnel engineering. The production capacity is determined by the selected model and geological conditions.

(4) anchor spraying machinery mainly includes anchor trolley and concrete jet machine. It is mainly used for concrete spraying and driving anchor rod in rock mass when tunnel working face is supported.

(5) Full-face tunnel boring machine and shield machine

II. Configuration and combination of main machinery and equipment in highway engineering

1. The general principles of construction machinery selection are: adaptability, advancement, universality, specificity and economy.

2. For earthwork excavation, the selected machinery and equipment mainly include bulldozers, scrapers, excavators, loaders and dump trucks.

3. For the stone excavation project, the selected machinery and equipment mainly include excavators, bulldozers, mobile air compressors, rock drills, blasting equipment, etc.

4. For subgrade plastic engineering, the selected machinery and equipment mainly include graders, bulldozers and excavators.

5. Configuration of main machinery and equipment for pavement base construction

(1) Mixing equipment for base materials: a complete set of stabilized soil mixing equipment is used for centralized mixing (factory mixing) and a stabilized soil mixer is used for on-site mixing (road mixing);

(2) Paving and leveling machinery: including mixture paver, grader, stone chips or field material spreader;

(3) Shipping machinery: loaders and transport vehicles;

(4) Compaction equipment: roller;

(5) Cleaning equipment and maintenance equipment: cleaning vehicles and sprinklers.

6. The construction equipment of cement concrete pavement mainly includes concrete mixing plant, loader, transporter, distributor, excavator, crane, slipform paver, leveling beam, napping curing machine, seam slitting machine, sprinkler, etc.

3. On-site management of construction machinery

1. Make preparations before construction

2. Use management of machinery and equipment

3. Establish responsibility system for machinery use

4. Management of operators

5. Management of machinery and equipment files.