Method Statement
1. Earthworks
1.1.1 Method for earthworks
The work shall be carried out by a road work team with construction equipment, and quality follow-up control shall be adopted during the construction process to assure construction quality for each procedure.
1.1.2 Construction Method and Process Flow
1.1.2.1 Topsoil clearance and grubbing
Bulldozers will be employed for clearance and grubbing of the topsoil assisted with loader for loading and dump truck for the disposal thereof. Trees shall be cut down manually but the stumps shall be removed using an excavator.
Existing concrete structures shall be demolished by breaking hammer assisted by manual la
bor and disposed by using dump trucks to a disposal area designated by the Employer.
1.1.2.2 Subgrade Excavation
1) Excavation of unsuitable materials and etc.
Using excavator, loader and dump trucks for removing unsuitable materials which will be disposed at place designated by the Employer.
2) Excavation works
Excavation will be carried out section by section.
The common excavation shall be performed by excavator, loader and dump truck. As for rock excavation, a crawler mounted drilling machine with air compressor will be employed for shallow hole blasting operation to split and loose the rock, the excavated materials will be removed and disposed by dump truck.
The process flow of common excavation is as follows:
Demarcating the excavation line after survey →original ground clearance →mobilizing equipment into position→excavation and disposal
The processing sequence of rock excavation by blasting operation:
Surface clearance →drilling machine in position→drilling by drilling machine →charging the hole method英语→blasting→inspection and clearance
Since the rock excavation of the project is 22143m3 in volume, some experienced and competent experts will be assigned for conducting and supervising the entire blasting operation, so as to ensure the safety and efficiency.
1.1.2.3 Subgrade Filling
1) Earth Filling works
Filling in horizontal layers and compaction in layers shall be used in construction. The thickness of each loose filling layer. Filling material shall be delivered to the site by 16m3 d
ump trucks and leveled firstly by bulldozers and then by grader for precise leveling after it is filled in filling area, and then rolled with vibration and static compaction by using single-drum vibratory road rollers and static rollers respectively. Small compactor shall be used where roller can no reach.
During construction, thickness for each layer, leveling, water content, and compaction scope and number of compaction shall be controlled strictly. Only when the previous work is approved and accepted by the Engineer after inspection, then filling of next layer can be made. Pile up filling by dump truck or overfilling is not allowed. The spoil is required to be leveled and compacted to prevent environmental contamination.
The construction works shall be properly arranged taking due account of rainy season, so as to avoid working in rainy days.
Flow-chart for filling works of subgrade earthwork:
Inspection and accepted
   
2) Rock Filling
Rockfill shall be used for filling in soft ground areas, as for culverts and wall back filling, rock filling material to be used shall be selected. Silt and soft materials will be removed before filling.
Construction method of filling and compacting in layers shall be adopted for rock subgrade. Thickness of filling and compaction for each layer shall be controlled within 250mm.
Flow-chart for rock filling of subgrade:
Unqualified
Construction method: Excavators and dump trucks shall be used for loading and transportation, bulldozers in large horse power shall be used for leveling and grading, joint filling by manual labor, and single-drum vibrating rollers and steel rollers shall be used for compaction.
2.2 Construction Method for Cement stabilized Natural Gravel Subbase Course
1) Construction plan
Mixture used for cement stabilized natural gravel sub-base in thickness of 250mm shall be mixed at mixing plant, and paver will be used for subbase laying in one operation. To cover the full width, paving shall be performed by paver in two times. And compaction shall be done using a vibrating roller and a tyred roller, the workmanship of shoulder with subbase material is as same as that for cement stabilized natural gravel subbase.

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