Clearing and Grubbing(C&G):
A good construction practice to follow cutting, removing and disposing of all unsuitable materials such as trees, bushes, shrubs, stumps, roots, grass, weeds, and top organic soils up to a minimum depth of 150mm from the road construction area known as site clearance-clearing and grubbing(C&G). During the site clearance-clearing and grubbing phase, primary access is created to facilitate equipment movement and delivery of construction materials for other construction activities like cross drainage structure which are underway at several locations.
Methodology for Site Clearance – Clearing and Grubbing:
Equipment for C&G in road construction:
The following sets of equipment as necessary for the planned progress are:
- Excavators / Backhoe –JCB
- Tipper /Dumpers
- Crawler Dozer with ripper arrangement
Site Handover and ROW marking:
- Based on the proposed planning/requirement, the work operation may be carried out part by part or as instructed by the Engineer.
- The stretch where the activity is to be carried out shall be taken over from the Engineer. A document of handing over and taking over shall be maintained.
- Rough alignment of the road, including the extent of ROW and fill-width, should be marked and approved by the Engineer.
Also, Read: Subgrade – Steps for Preparation of Subgrade
Assessment of Utilities and necessary permission/clearance:
- On taking over the site, a list shall be prepared of surface obstruction for the properties and other facilities/utilities required to be dismantled/shifted for construction of road and inform the Engineer or his representative for further instruction.
- Depending upon the information available, trenches of width (600mmx900mm) is to excavate across the proposed road up to a depth of 500mm from the general ground level to know the position of sub-surface utilities. A list of such utilities is to be submitted to the Engineer or his representative for his further instruction.
Site Clearance – Clearing and Grubbing Operation(C&G):
- Site clearance shall commence after handing over the site and getting the necessary permission/clearance for cutting trees, dismantling structures/obstructions and shifting utilities (Overhead and underground) from the client or as directed by the Engineer.
- Diversion and filling of existing watercourses along the road alignment attended as per following procedure by getting approval from Engineer or his representative.
- In the case of small isolated water bodies with stagnant water falling within embankment: Stagnant water shall be removed, provided feasible, by bailing out or pumping using surface discharge pumps or making channels leading to adjacent low-lying areas, if available. Care shall be taken against damage to the works, crops or other properties while discharging water.
- Diverting an existing channel from the sites of the embankment to a new channel: All vegetation and Soft deposit of the old channel shall be removed up to a depth of 150mm. After cleaning, the side and bottom of the existing channel shall be filled with suitable material and compacted as per standard specifications.
- Dismantling of PCC/RCC, stone/brick structures shall be removed up to the limits and extent specified in the drawings or as up as per instruction of the Engineer after recording the measurement jointly.
- Bituminous pavement/wearing courses shall be dismantled as specified in the contract with prior approval of the Engineer after recording the measurement jointly.
- Records of trees to be cut and stumps to be removed shall be recorded jointly before starting the tree cutting work. All trees, stumps, etc. falling within excavation or fill lines shall be cut to such depths below ground levels that, in no case, these fall within 500 mm of the subgrade. All vegetation such as trees, stumps, shrubs, roots, grass and all other harmful material unsuitable for incorporation in the embankment/sub-grade within fill lines shall be removed properly.
- All excavations below the general ground levels arising out of the removal of roots, stumps etc., shall be filled with suitable material and compacted thoroughly using mechanical or manual means as per site conditions in layers not exceeding 200mm thickness to achieve specified compaction.
- Backfilling around structures, wells etc., shall be done after dismantling with the help of excavated/approved materials and compacted to the required density as directed by the Engineer.
- The topsoil obtained from clearing and grubbing shall be stored along the ROW available as required for spreading on the embankment slopes and other Environmental aspects.
- All unsuitable material in the Engineer’s opinion arising out of the site clearance operation shall be disposed of as per MORTH Specifications Clauses 201 & 202 at locations/dump areas (within or outside ROW) made available by the Employer/Engineer.
- After Clearing and Grubbing and making the ground ready for further embankment, work shall commence only after establishing and referencing the centerline, establishing TBM and recording the OGLs jointly. A soil sampling for that ground shall be taken jointly for further testing.
Also, Read: Wet Mix Macadam Construction and Quality Control