Tag: planning of earthworks

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Earth Works Road Construction

Pre-construction Planning & Programming of Earthworks

This is last section of pre-construction planning & programming of earthworks constructions  and stick to this procedure will bring-down the unnecessary problems in future.

(k) Material Quantities and Lengths of Haul. It is necessary to determine the quantities of material to be led to embankment, spoiled or borrowed. These quantities and the lengths of hauls must be determined so that appropriate plant can be selected and the work planned. The mass haul diagram is provided in the documents for this purpose.

(l) Selection of Material. The job must be planned so that the various materials available are used wherever possible in the position in the embankment where they will be most advantageous.

(m) Testing and Quality Control. The resource needs must be determined and testers and equipment must be ready so that testing can commence as soon as the earthworks begin.

(n) Plant Selection. It is important to select the correct type and size of plant required to carry out each task in view of the site conditions, type of material and the outputs required. Plant should be selected so that :

(1) As far as possible, the plant fleet is balanced.

(2) There is sufficient plant to achieve the desired progress of earthwork constructions.

(3) The plant fleet is flexible enough to avoid a major holdup if one item of plant breaks down.

(4) The right type of machine is used for each task.

(5) Each machine is of sufficient capacity to carry out the  earthwork job  effectively and efficiently.

In some instances circumstances may dictate selection of plant other than the ideal. However whatever the plant allocated it is necessary to establish its time of availability, and to estimate the operator hours, plant hours etc… relevant to each task.

(o) Provision of Earthwork. It is essential to determine the order in which work should be carried out and to plan so that operations are not spread out haphazardly as this makes supervision difficult and increases the time lost by plant traveling between tasks. Earthworks job should progress on a face with finishing and trimming being carried out as the work proceeds.

(p) Earthworks Program. The detailed earthwork program should show each major item of work, quantities, timing of operations and plant requirements.

In drawing up the earthworks program the engineer must consider all available alternatives. The earthwork construction program may need to be varied to match the resources available and to even out the demand for particular machines so as to provide continuity of work for them (e.g. a program which requires heavy dossers for six weeks then none for the next two weeks, and finally three for the next twelve weeks, obviously should be re-examined).

As summery of  Pre-construction Planning & Programming of Earthworks ahead of works are begin can be minimize future delays of construction work.

Categories
Earth Works Road Construction

Pre Constructions Planning and Programming of Earthworks in Hilly Areas

We will discussed main points about the  pre constructions planning and programming of earthworks in hilly areas  in here. There is an additional steps to carry out in special area such as hill country or hilly areas, steep slopes areas. In steep country an inspection should be made for unstable areas likely to slip. These may be indicated by :-

• seepage and springs;

• lush growth of vegetation in local areas (indicating ground water);

• trees and bushes leaning downhill (indicating slippage of the surface material);

• bent trees or lack of vegetation in an otherwise timbered area (indicating large slides).

(i) Cuttings Drainage works. Culverts and other drainage works must be planned in conjunction with the earthworks construction. There must be sufficient lead time (float) provided in the program between these two operations on any section of the works to allow for possible delay in supply of pipes, delay due to wet conditions, and the time required to cure cast-in- place culverts etc. The timely construction of drains diversion banks, culvert inlets and
outlets etc., must be taken into account in this planning of earthworks construction.

(j) Assessment of Likely Material. An assessment must be made of the material likely to be found in the cuttings and of foundations for embankments so that the correct plant and methods of working can be selected for earthworks construction.

It is a sound precautionary measure that all large cuttings should be test drilled prior to excavation. The cost of drilling is small compared with the cost of wrong decisions as a result of lack of information. Test drilling should be done prior to designing of the earthwork construction job.

Before commencing earthworks construction the report on the material, the drill logs and any cores recovered should be carefully examined. The cores are retained by laboratories and the engineer should make arrangements to inspect them at the laboratory or have them transferred to the site office. The geologist and engineer who prepared the report will normally be available for discussions.

The test drilling mat be supplemented by a seismic survey. In such a survey, an idea of the hardness of rock strata is obtained from the velocity with which a shock wave is transmitted through the rock. The steel plate with a hammer. The velocity is determined by the time the shock wave takes to travel from the source to a series of recording stations laid out in a straight line.

Various tables are available for interpreting the hardness of rock from seismic velocities. Caution is required in accepting such interpretations as the degree and orientation of the jointing of the rock and size and type of machines to be used for ripping and hauling are significant factors in determining whether a particular interpretation can be economically applied.

Any existing cutting should be inspected. Where possible, trial excavation and ripping of accessible material should be carried out.

There is some points to discuss further regarding the subject of  earthworks construction  and how to start constructions and estimate time, machinery and manpower requirement etc.. and hope to discuss in next post.

Categories
Earth Works Road Construction

Pre Constructions Planning of Earthworks

We discussed about planning of the  earthworks operation  in the previous post. All the earthworks construction and all the possible problems may arise has to plan before start the constructions and here we are going to outline the pre constructions planning of earthworks operation.

All the constructions matters which may arise and which  should  be  considered  at  the  pre construction  planning  and  programming  stage include :-

(a)  Job Documents.  Prior to any planning a through examination must be made of the project plans and specifications.

(b) Clearing and Surface Preparation.     To avoid delays it is necessary to plan for this work to be carried out well ahead of the earthworks construction.

(c)  Provision of Water for earthworks.  Where  there  is  no  permanent  water  supply  available,  all the temporary water supply reservoirs, rivers,streams or any alternative must be located prior to commencing work  so as to provide water for compaction.

(d) Service Alternations or Utility Line Relocation where earthworks constructions to be start.  Re-locations  to  telephone,  gas,  electricity  services  etc.  are  a  frequent source  of  delay.  Arrangement  for  these  alternations  should  be  made  as  early  as  possible. Service authorities often need a great deal of time to plan and design the alternations, obtain materials and program work to fit in with their normal commitments.

(e)  Slow and Difficult Work. Any section of the work which  may  be slow and difficult (e.g. a rock cutting) should be programmed for an early start so as to avoid possible delays to the whole earthwork job, consistent with other factors e.g. utilization of resources, overall economy.

(f)  Provision for Traffic.  The all the earthwork constructions must be planned to minimum inconvenience to  traffic , and should  be  completed  in  sections  avoiding  long  lengths  of  side  track(bypass).  Sections  where  side tracking(bypass) is difficult should be completed as quickly as possible.

(g) Wet Weather Effects -Rainy seasons. Sections of the work areas likely to be affected by rainy season or bad weather (e.g. boggy  flats) should  be constructed during the  first available dry period. If  left towards the end  of  the  job,  wet  weather  could  delay  the  completion  of  the  earthworks  and  additional  costs may have to be incurred to treat saturated areas.

(h) Saturated and Unstable Areas.  The ground on which embankments are to be placed should be  inspected  for  wet  or  saturated  areas  so  that  these  can  be  treated  well  ahead  of construction.

Pre construction planning of  earthworks in road constructions  may vary with large no of factors. We are going to discuss, how to determine daily productions, how many machines are going to apply and material haulage, selections of materials etc.And also effect different geographic locations like hill areas, marshy areas for earthworks in road constructions.