first, quality control in construction preparation stage
before the construction of municipal road engineering, quality management personnel must work out an implementable quality control plan according to the actual characteristics of road engineering, strengthen their understanding of the general situation, hydrology, geology, meteorology and surrounding environment of municipal road engineering, set up a project department to meet the construction needs, formulate scientific and reasonable quality control measures, and make good preparations for the construction stage. According to the characteristics of the project, the work instruction manual that meets the actual situation on site is compiled, which provides an important basis for the construction of municipal road follow-up projects. Before construction, the project management personnel shall make technical disclosure according to the construction scheme of the road project, do a good job of technical disclosure before construction, and jointly review the design drawings, and report the questions on the drawings to the relevant departments in time to avoid affecting the normal construction of the project, so as to ensure that the quality of the whole municipal road project meets the design requirements.
second, the quality management in the construction stage
the construction stage is the implementation stage of the design results, which has a direct impact on the quality of municipal roads, and the quality management in the construction stage must be strengthened. Quality management is the most fundamental management in road engineering construction management. In order to ensure the construction quality of road engineering, it is necessary to strengthen the comprehensive and whole process quality management of road engineering. Quality management personnel must do a good job of pre-control, in-process control and post-control control, and especially strengthen the management of key working procedures and important concealed works. Quality management personnel must carry out on-site quality control in strict accordance with the requirements of various technical standards and specifications, and deal with violations of road engineering construction in time to ensure the construction quality of road engineering. 1. Strengthen the quality control of subgrade filling. Before backfilling, choose the filling method that meets the requirements according to the characteristics of road engineering. The thickness of each layer is determined according to the parameters of backfill compaction in the filling compaction test section. In actual backfilling, a set of elevation points are set for the general embankment at 2m, and the compaction thickness of each layer is controlled to be below 3cm and above 2cm, with the maximum virtual paving thickness of about 35cm. According to the specific conditions of the subgrade on site, reasonable filling methods should be adopted. For example, when the terrain changes greatly, backfill should be carried out in layers from the lower part, from both sides to the center, and the backfill on both sides of the slope should be controlled to exceed 3cm to ensure the quality of rolling. 2. Paving and leveling. After filling a layer of thickness, first level it with bulldozer, and then level it with grader, to ensure that the filling layer reaches a smooth and uniform state in the longitudinal and transverse directions, and make the surface of the roller wheel of the roller compact the contact surface evenly. When paving, it is necessary to leave 2%~3% transverse drainage slopes on both sides to ensure that there is no water on the subgrade surface. According to the relevant parameters determined in the test section, the optimum water content is selected. When the water content exceeds +2% of the optimum water content, the method of paving on the subgrade and loosening the soil with a hanging tiller to dry in the air is adopted to reduce the water content of the fill. 3. Rolling. Before rolling, check the layered thickness and smoothness of the filling layer to ensure that its thickness and smoothness meet the requirements of rolling. In order to ensure the quality of rolling, at the beginning of rolling, the loose soil is pre-pressed with a small smooth roller, and then rolled with a large-tonnage vibratory roller. Compaction must be carried out in strict accordance with the specifications, for example, according to the procedures of rolling the edge of subgrade first, then rolling the subgrade in the middle, advancing and retreating longitudinally, and rolling slowly first and then quickly. In the rolling process, the wheel tracks of the roller traveling back and forth must overlap by 1/2 wheel width, the vibratory roller should overlap by 4~5cm, and the adjacent two areas should overlap longitudinally by 2.m The compaction operation should be unbiased, dead angle and even. 4. Subgrade renovation and frost boiling treatment. When the subgrade filling and excavation is close to the design elevation, surveyors should strengthen the measurement of the elevation of the top surface of the road bed and the width on both sides of the center line of the road bed in the transverse and longitudinal sections, and deal with the projects beyond the allowable range of measurement in time. For the excavated subgrade, the elevation of its top surface should reach the design elevation to ensure that the compaction degree after rolling meets the design requirements. If the soil material has a small water content, it needs to be watered to make the water content reach the optimal water content state. For example, when the water content of road subgrade is high, when it vibrates during vehicle running and rolling, it must be treated with boiling. When local boiling, the soil material should be replaced with soil material with appropriate water content, and then rolled. 5. Road bed renovation and rolling. Before the road bed renovation, surveyors should accurately set out the longitudinal center line, width and transverse slope of the road bed to ensure that the elastic modulus value of the road bed soil foundation meets the design requirements, and the soil layer 3cm below the top surface of the road bed must meet the compactness requirements of the design and specifications. 6. Pavement construction quality management. Before construction, the "three-level technical disclosure" shall be implemented in strict accordance with the construction technical disclosure system and implemented in practice. Before the pavement construction, strengthen the inspection of the quality of the lower bearing layer. When the pavement construction is not satisfied, it is forbidden to carry out the construction of the pavement subbase and base. Before pavement construction, a section with a length of 1~2m is selected as the test section, and the parameters of each layer of pavement are determined, such as checking the rationality of the proposed construction scheme and method, the construction organization and the number and model of construction machinery. Through the pavement test section, the construction process and method can be optimized, the construction efficiency of pavement operation can be improved, the responsibilities of each post personnel can be clarified, and the construction quality of pavement can be ensured. According to the relevant parameters of the test section, during the construction of graded macadam subbase, firstly, ensure the accurate batching and uniform mixing of the mixture, secondly, there is no segregation of coarse and fine particles, and finally, ensure the degree of compaction above 96% under the optimal water content. During the construction of lime-soil subbase, it is necessary to strengthen the inspection of the quality of the lower bearing layer, otherwise, the construction work is prohibited. When paving the mixture, bulldozers and scrapers shall be used to operate according to the loose paving coefficient of the test section. After paving and shaping the mixture, it shall be compacted according to the compaction parameters of the test section, and it shall be rolled from the inside to the outside by the horizontal curve section and the road roller, especially on both sides of the road surface, for 2~3 times as far as possible. In the process of rolling, if the "spring soil" is loose and peeled, it should be turned over in time to carry out construction again to ensure that the construction quality of the pavement meets the design requirements. During the construction of cement stabilized macadam base, the center line of the road should be restored at the top surface of the subbase. For the straight section, a pile should be set every 15~2m, and for the flat section, a pile should be set every 1~15m. Besides, marker piles should be set outside the shoulder edges on both sides. The surface of the lower bearing layer should be flat and solid, and the flatness and compactness of the lower bearing layer should meet the design and specification requirements. Mark the design elevation of the edge of the cement stabilized base with obvious marks on the marking piles on both sides to ensure the quality of the paved cement stabilized macadam base. 7. keep healthy. After the road pavement construction is completed, it is necessary to strengthen the watering of the finished surface for health preservation. Generally, the pavement needs to be kept moist for 7 days. In case of hot weather, the intensity of health preservation should be increased. During the health preservation period, vehicles are prohibited from passing, and special personnel are assigned to carry out traffic control. After curing, spray asphalt to seal the oil layer immediately according to the design requirements.
3. Quality control in the completion stage
The completion stage is the final stage of quality control by the construction unit, and its quality is the reaction of the whole project construction process. Before the completion acceptance, the construction unit must carefully collect all kinds of materials needed for the completion acceptance, file them by category, and compile materials that meet the requirements of the completion acceptance. Only after self-inspection meets the requirements of the completion acceptance can the road project be formally accepted to ensure the overall quality of the completion acceptance.
to sum up, municipal road engineering generally has many working procedures, long cycle and strong professionalism. Combining with the actual characteristics of road engineering, we should establish and improve the quality management system, carry out construction in strict accordance with the requirements of municipal road design and specifications, and correct and solve problems in time when found, so as to ensure the construction quality of municipal road engineering meets the design requirements.
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