ROAD CROSS -DRAINAGE AND THE SUB -SOIL MOISTURE CONTENT OF THE SUB -GRADE MUST HAVE AN APPROPRIATE DESIGN AND SURVEY WORK

It is necessary to follow a survey work of the road before designing the sub -soil drainage system for the road, where water conditions in the sub -soil must be verified. Free water can be intercepted or controlled and a high water table can be lowered by the installation of sub -soil drains. The position of the drains should be such that the water table is maintained at least 1.2 metres below the formation levels in case of the hilly areas and in the case of concrete roads the base of the slab shall not be less than 30 cm above the anticipated water level in the said drains or the surrounding areas. The back fill used in the drainage trench should consist of a properly designed filter material, especially where the sub soil is liable to cause silting of back fill . It is very clear from the beginning that stability of the roads can only be maintained if the soil foundation remains in a relatively dry condition. As the moisture content increases the strength of sub -soil decreases. This effect of the moisture content is more marked in the clay soils than with granular soils such as sands and gravels. Further the control of the moisture content of the sub grade is an essential feature of a good road. Water moving freely under the action of gravity can effect the moisture content of a sub grade by reaching it through previous road surface, by seepage and by rise in level of the water table. Moisture can also enter or leave the sub grade, either as a liquid or as vapour, under the action of forces entirely inherent in the soil itself. Moisture content also increases when the above evaporation (movement of moisture) is stopped due to putting on top of an impervious layer of road surfacing. About one metre below the road surface moisture content stays about the same.Hence the main object, therefore is to maintain the sub soil under and adjacent to the carriage way in as uniform a condition as possible by preventing moisture entering the road bed rather than by drawing all water from it.It is not necessary to drain granular soils such as sand and gravel because they are not apprreciably affected by changes of moisture content, however water can't easily be drained from heavy clays because it is held in suspension by capillary forces as in blotting paper:-- Er Fateh chand Guleria, Director RTI welfare Association registered number HPCD, 3552 , Bilaspur HIMACHAL PRADESH phone number, 9459334377

ROAD SIGN BOARDS ARE NECESSARY ALONG THE ROADS TO SPECIFY THE DUMPING SITE

DUMPING SITES ALONG THE ROADS :-- It has become general practice of the various agencies to dump the un useful material along the valley side of roads without taking into consideration the position and situation of existing cross drainage structures and the profiles of the catchment area covered by the study of impact assessment realised by the code of schedule for observation related and pertinent to the contour plan and survey sheets maintained by the survey of India list by way and virtue of which the system of drainage stood blocked during the heavy rains and create problem of floods which destroys the infrastructure existing in the lower ballot / areas along the streams / rivers even though the such materials also reacts as land slides for the lower level of living souls and the circle.The Department of the Public Works must avoid this practice and dumping sites along the roads should be marked at specific places where no obstruction may be occured to the drainage water across the roads and Road side boards may be fixed to avoid the expanding losses due to heavy rains as creating danger to the lower level living areas /souls because of unstable intensity and pressure volume of the heavy rain water .