What are the technical points of "earthwork excavation" and "construction technology"?

Special plan for earthwork excavation \x0d\ x0d \ 1. Earthwork excavation \ x0d \ The foundation pit of this project adopts the method of combining mechanical excavation with manual trimming for earthwork excavation. Before earthwork excavation of foundation pit, a special plan shall be submitted to the supervisor and implemented after approval by the owner. In the process of earthwork excavation, it is necessary to do a good job of axis and elevation measurement, drainage and other related cooperation at any time. Slope support should be carried out when the foundation pit is close to roads and municipal existing buildings to ensure the safety of roads, municipal pipelines and existing pipelines and buildings and the smooth construction. Slope support should be undertaken by units with corresponding design and construction qualifications. \x0d\ The second earthwork excavation of shops along the street in this project can be carried out only after the construction period of engineering piles meets the requirements. The first shop along the street must wait for the supporting piles to be completed and reach the maintenance period before excavation. The earthwork of the foundation pit is excavated in different periods, and finally the earthwork is transported out of the pit by a long-arm excavator. Earthwork of foundation pit in each block shall be excavated symmetrically in layers and blocks. \x0d\ Excavation and transportation method: Large-scale excavation of foundation pit must follow the principle of "slotting support, first supporting and then digging, layered excavation and no overbreak". It is forbidden to dig in place or overbreak at one time. Dump trucks are used for mechanical excavation and transportation, and the transportation distance is controlled within the shortest distance. \x0d\ During excavation, open drains and collecting wells are set around the basement, and then sewage pumps are used for continuous pumping and dewatering. At the same time, in order to prevent rainwater from invading, the surface water in the excavation range is diverted by excavating the drainage ditch around the upper part of the foundation. In the process of earthwork excavation, assign special personnel to clean the ground drainage ditch, pump water in time and discharge it out of the field in an organized manner. \x0d\ When excavating at the bottom of the foundation pit, be careful that the bucket does not touch the engineering pile or roll on the top of the pile. It is forbidden to pile soil or load around the foundation pit. My construction unit always pays attention to the change of soil quality and the surrounding conditions of foundation pit support. Earthwork for foundation pit excavation is strictly prohibited to be piled on the outside of foundation pit. When the portal frame is reached, the portal frame foundation pit shall be excavated first, so that the portal frame foundation and portal frame installation can provide convenience for the transportation of basement construction materials. \x0d\ When the earthwork excavation is about 200mm above the design elevation of the bearing stratum at the bottom of the pit, it should be repaired manually. After reaching the design elevation, the pit bottom shall be protected, and the site supervisor, survey institute and designer shall be invited to check and accept the foundation trench. After acceptance meets the requirements, it is forbidden to expose the natural soil at the bottom of the pit for too long, so as not to affect the soil structure. Cushion concrete construction should be carried out in time, then cushion concrete should be poured, and then local excavation of deep foundation pit and pile cap should be carried out one by one. According to our construction experience and calculation results, the masonry height of brick tire mold is 120 when it is within 800mm, 240 when it is within 1500 mm, and 370 when it is greater than1500 mm. M7.5 cement mortar can meet the requirements of retaining soil and strength, and the powder cement mortar within 20mm is 1:2 thick. \x0d\ In the process of foundation pit excavation, engineering professional surveyors shall conduct on-site measurement at any time to ensure the correct depth and position of earthwork excavation, and shall not disturb the original structure of basement soil to prevent foundation pit from overbreak and wrong excavation. If they find any discrepancy with the design of geological report or other abnormal conditions, they should keep in touch and communicate with the personnel of site supervision and design department at any time, study and solve problems in time to prevent accidents. \x0d\\x0d\ II。 Foundation pit drainage measures \x0d\ During the construction stages such as earthwork excavation, basement structure, waterproof outside the side wall and earthwork backfilling of foundation pit, the on-site foundation pit drainage will be directly drained according to the basement temporarily, and drainage ditches and collecting wells will be set around the bottom of the foundation pit for drainage, and then the sewage pump will be used for continuous pumping. \x0d\ In the process of foundation, in order to prevent rainwater from invading, the surface water within the excavation scope is diverted by excavating intercepting ditch around the foundation pit edge at the top of the foundation to prevent the surface water from soaking the into the pit; There are simple drainage ditches and collecting wells in the foundation pit, which are pumped around the foundation pit by water pump for dewatering. The bottom of the ditch and the bottom of the collecting well shall be kept 0.3~0.5m lower than the excavation face, and the bottom of the collecting well shall be about 1m lower than the ditch bottom, with a diameter of 0.7 ~1.0m. The shaft wall shall be temporarily supported, and the bottom shall be paved with 0.3m thick gravel, and the drainage ditch shall be 0.3m away from the toe of the slope. The drainage of foundation pit should be reduced to 500mm below the construction surface, and it should continue until the waterproofing and backfilling outside the basement structure is over, and the building can not stop completely until its own weight overcomes buoyancy. In the process of foundation construction, assign special personnel to straighten out the surface drainage ditch, pump water in time, and discharge it out of the field in an organized way. \x0d\\x0d\ III。 Safety precautions for earthwork excavation \x0d\ 1. Earthwork excavation method and excavation sequence shall be carried out according to the supporting scheme and drainage requirements. When partial or full slope excavation is adopted, the slope gradient should meet its stability requirements. \x0d\2。 Excavation should be carried out from top to bottom, and it is forbidden to dig the toe of the slope first. When there are no reliable measures, the soft soil foundation pit should be excavated in layers and the height should not exceed1m. Each excavation depth and excavation sequence of earthwork must meet the design requirements. Within the pit (trench) 1m, no soil or materials shall be piled, and no machinery shall be parked. \x0d\3。 When the excavation depth of foundation pit is greater than the foundation depth of adjacent buildings, we should keep a certain distance or take slope support and reinforcement measures, and observe the settlement and displacement. \x0d\4。 If unknown objects are found during the construction, the construction should be stopped to protect the site, and the local authorities should be reported immediately for handling. It is forbidden to knock or play with them at will. \x0d\5。 Check the stability of the working slope of the excavator, and take reinforcement measures when it does not meet the requirements. When digging below the shutdown operation surface, backhoe or pull shovel operation should be selected. When using the front shovel, the excavation depth should strictly conform to the specifications. When mechanical excavation is used for supported foundation pit, support collision during operation should be prevented. \x0d\6。 Workers who cooperate with the excavator should work outside its working radius, and they can only work within the working radius after the excavator stops rotating and brakes. \x0d\7。 After excavation to the elevation of the pit bottom, the foundation engineering construction of the next working procedure should be carried out in time to reduce the exposure time. If the next process cannot be carried out immediately, a 300 mm thick covering layer should be reserved. \x0d\8。 When the construction depth of the foundation pit exceeds 2m, the edge of the pit shall be protected according to the requirements of aerial work, and the operators shall have special ladders up and down. When the interchange operation is formed in deep foundation pit construction, the basement, personnel and transportation channels should be arranged reasonably, and the protective layer should be set to prevent falling objects from injuring people. \x0d\\x0d\ IV。 Protective measures for foundation pit \x0d\ Protective measures should be taken after foundation pit excavation. For parts with poor soil quality and deep excavation, waterproof cloth should be used to prevent landslides caused by rain. Drainage ditch should be set around the upper part of the foundation pit, and the rainwater in the drainage ditch should be pumped out in time. Protective railings are erected around the foundation pit with steel pipes, and warning lights are hung at night to ensure safe construction. \ x0d \ x0d \ v. Others: \ x0d \ On-site underground pipeline information shall be submitted in writing by the construction unit. If it is not submitted, the construction unit thinks that there is no underground pipeline. If there is any damage during construction, the construction unit shall be responsible for it. The construction and quality control of other axes and elevations will not be described in detail, and the construction will be organized according to the requirements of construction organization design.