Information Technology Reference
In-Depth Information
pavement structure will soak in the layers of pavement structure materials, it can make
pavement intensity drop and increase the deformation, thereby, it makes the bearing
capacity of the pavement structure reduce. In the end, it results in pavement damage. In
large quantity and fast driving conditions, part of asphalt concrete will become loose. If
the rainwater enters and is detained in the asphalt concrete pavement, free water in
pavement will produce a lot of pressure and it will erode fines in the surface layer of
pavement, this produces mortar, finally, the mortar will be pressed into the road
surface. In the case of the large number of mortars, the pavement may produce holes. In
the case of the small number of mortars, the Pavement somewhere produces shaped
crack or deformation. If the pavement produces shaped crack, deformation or holes, the
rainwater will more easily penetrate into it, and form a vicious cycle, finally it lead to
road damage.
3 Rainfall Infiltration Process and Rule Analysis
3.1 The Process of Rainfall Infiltration
Saturated seepage theory considers that the soils are saturated soil below the
groundwater, and they are dry above the groundwater. In fact, the regions above the
groundwater level are unsaturated. Infiltration of rainwater is essentially water
movement in the soil aeration zone. It is a type of two-phase flow process, which is very
intense along with the change of time and space [3]. When the rainfall intensity exceeds
soil infiltration capacity, the pavement will emerge runoff or water accumulation, and
form the expanding saturated zone, at this time, the water movement in soil is
saturated-unsaturated flow. When the rainfall intensity is lower than infiltration
capacity, infiltration process will be affected by water supply capacity. Rainfall
infiltration process can be divided into the following three processes [4]:
(1) Infiltration process. The infiltration is the process which the moisture enters into
the soil, this process is mainly affected by capillarity and matrix suction.
(2) Moisture redistribution process. Moisture redistribution process is after
infiltration, moisture movement is affected by capillarity and gravity. In this process,
moisture absorption and moisture desorption are exist at the same time, between
moisture absorption process and moisture desorption process the soil - water
characteristic curve is dissimilar, and their curves are also dissimilar because of
different initial moisture content.
(3) Drainage process. Drainage process is mainly the moisture infiltrates to the deep
zone, and eventually supply to groundwater.
3.2 Rainfall Infiltration Rule
Rainfall infiltration water and underground water are interrelated, and it can make the
underground water level is greatly raised in a short time. In addition, the supply of
water by rainfall infiltration can increase the saturation of the soil, thus reduce the shear
strength of soil and the performance capability.
Search WWH ::
Custom Search