All necessary clearing and grubbing and topsoil excavation (where necessary) will be completed prior to the beginning of the excavation. The location will be demarcated to show the limits and depths of the excavation. The disturbing and spoiling material and vegetation outside of the expropriation limits will be avoided to the extent possible.
The excavation will be done to the formation level for the full construction width. The excavation will start either with bulldozers or excavators together with the construction of the slopes. The material that is excavated by excavator will directly loaded to the dump trucks and transported to the fill or deposit area.
For further 20 cm the existing material will be scarified, watered as necessary, mixed and compacted. The prepared formation will be in such condition that it will be well drained all times. All slopes, lines and grades will be true, and accurate and according to those on the drawings or otherwise directed and approved by the Engineer.
The material, which is tested and defined, as unsuitable material will directly hauled to the disposal areas that is approved by client and stored properly.excavation and backfilling
The material which is tested and defined as suitable material however not proper for fill operations due to water content or climate conditions will be loaded, hauled and stored in the deposits area. If the weather condition is not suitable for fill operation, the excavation will continue as mentioned above however the material will be transported to the deposit areas defined by the client.
Construction of fill layer consists of spreading of appropriate non-cohesive fill material by layers and compaction to the required level specified by design. Fill material shall be deposited to site by dump trucks and spread either by a dozer or a motor grader so that the spread layer will have a thickness according to the type of the material.
Compaction of material shall be handled using single drum smooth-pad rollers and/or single drum padded rollers. Compaction direction shall be from lower elevations to higher elevations and passes shall be performed so that drum of the roller will overlap its previous pass by %10.
Next set of passes shall not be performed unless a set of passes is completed on all lanes. Rollers shall perform their last passes without vibration so as to attain a smooth finishing surface. If fill material is too dry and having moisture below its optimum content, water trucks shall be utilized so as to attain optimum water content. In the case that fill material has a moisture content above optimum, material shall either be ripped and aerated or be waited until excess water self-drains or evaporates till optimum water content.
Once the required number of passes is performed on the entire strip of the fill, the degree of compaction shall be measured at a number of randomly selected points so that the number of test points represents the strip accurately.
Provided that target degree of compaction is reached, same procedure shall be followed for the next strip of fill. For the adjacent fill strips, material spreading process shall be performed so that one fill strip overlaps the adjacent one to assure stability and uniform behavior of fill layers.
The excavation will be performed with bulldozers and hydraulic excavators. The excavators will load directly from the excavation to the articulated dump trucks and the trucks will haul the material to the fill or waste area. The material excavated by bulldozers will be loaded to trucks by loaders. The material will be hauled to fill or waste areas.