The Study Of Interaction Between Soil And Underground Pipe Culverts

Underground pipe culvert in the daily production and life plays an important role,range from water pipe、sewage pipe, to oil pipeline over the water bridges and culverts, andits importance is self-evident, but often running different degrees of damage. Undergroundculvert is a hidden project, not easy inspection and maintenance, which high demands ofunderground pipe culvert design. Get both economical and safe pipeline design, it is moreaccurate to determine the role is particularly important in the load on the pipe and thevertical earth pressure design load. The largest city in the ditch fill pipeline domesticresearch is not yet mature, and thus the hydraulic structures load design specifications notgiven calculation method.This paper summarizes and analyses the domestic and international research onvertical earth pressure of the underground pipe culverts, as well as the influencing factors.For the straight groove buried rigid pipeline, a new calculation model of surface earthpressure linear slip is established, based on the twin shear unified strength theory, thendeduced the calculation formula of soil pressure. Compared with the traditional earthpressure calculation method, the new earth pressure calculation method can be consideredinfluence of intermediate principal stress on the pipe earth pressure, so the earth pressuretheory calculated value is closer to the actual stress of the pipe.Using finite element software Midas/GTS for the numerical analysis of rigid pipe,through the establishment of the contact element to simulate the relative slip of fillingbetween the pipe and trench, reveal the influence law of pipeline depth、wide pipe trench、the trench slope on the pipe earth pressure and peritubular fill stress, displacement field.Research shows:①friction angle and cohesion parameter of Goodman interface elementsettings have little impact on the results of numerical simulation;②There also has plane ofidentical settlement in the filling soil of ditch fill pipeline, the depth of plane of identicalsettlement is influenced by both depth and groove width;③The impaction on the the rigidgroove administered pipe tube top soil pressure of groove width is lower than depth.Coefficient of earth pressure increases with increasing slot width, then tends to a constantvalue, and its growth rate and setting are impacted by the depth;④Filling horizontaldisplacement is influenced by the slot width, while having a small slotted tube themaximum horizontal displacement appears on top (bottom) on both sides about45o;⑤Thehorizontal earth pressure distribution of tube side shows saddle-shaped distribution;⑥Stress concentration emerge on tube top (bottom), the setting of cushion layer allows thebottom of the tube filling stress more evenly distributed, reducing the stress concentration; ⑦Trench support angle increases with the slot width increasing;⑧Rigid pipe top normalstress is larger than one on pipe side, which revels rigid pipe are shared by itsself-supporting load;⑨Grading slotted will not only increase the amount of earthwork, butalso will increase the value of the tube top soil pressure.