A Construction Simulation Of Backfilled Soil In Layer And Experiment Study Of The Earth Pressures On Culverts

With national economy developing by leaps and bounds, the culvert is widely used in water conservancy, highway, railway, etc .It can be mainly divided into two parts: channel-buried culvert and positive buried culvert. However, because lack of the reasonable earth pressure theory for design of these culverts, some of them fail in the period of construction or after completion of work for using smaller size of structure, in some case over big size of culvert structure are designed to be bear the uncertain pressures on the culverts and led to more cost. Based on the occasion above, the earth pressure theory and the method of load reduction are studied through model test and numeric simulation to find a reasonable earth pressure theory for the culverts beneath the high fill. The fruits of research in the thesis as follow:(1)A series of testing about stiff rounded culvert in the house have been carried on based on the stiff foundation and sand soil. Slope of trough wall; the condition of positive buried culvert. The result involves the earth pressure on the top of culvert, the lateral earth pressure and the displacement of the earth with the different height of backfill. The test results show the principle of variation of pressures on culverts beneath high fill is similar, it is that, even if the embankment is filled up to a higher height, the earth pressures can still partly transfer to the top of culvert, as a result the pressures on the culvert increase nonlinearly with the variation of height of fill and further the pressures.(2)There is connection between channel-buried culvert and positive buried culvert. Along with the increase of H/B, channel-buried culvert grow positive buried culvert. With the increase of H/B, positive coefficient of vertical soil pressure, K_v, decreases before ascend. K_v is above 1, the max of K_v is 1.45.Positive coefficient of horizontal soil pressure, K_h,is above the value by active earth pressure. With the increase of H/B, positive coefficient of vertical soil pressure, K_v, decreases before ascend. K_v is less than 1, positive coefficient of horizontal soil pressure, K_h, is less than the value by active earth pressure.(3)As the decrease of the slope and the increase of the width of the trough, that is to say, the slope of backfill is less than 1:1 or the width of the trough is four times than of the width of the span of culvert, the distribution of the channel-buried culvert is similar with that of positive buried culvert.(4)The theory of, so a new calculation model of earth pressure has been established in the paper, which also includes the formula of calculating the earth pressure of channel-buried culvert with the rectangular section and trapeze form the theory of M-S has been modulated. There is a conclusion that when the height of backfill is not tall, tall distribution of perpendicular earth pressure of channel-buried culvert is similar with that of positive buried culvert.