基础工程答案（Basic engineering answer）.docVIP

基础工程答案（Basic engineering answer） 1) the soil below the surface of a building site is: (1) medium sand, thick 2.0m, and the surface of the diving surface at 1m below the surface, saturated and heavy; (2) clay isolation layer, thick 2.0 m, heavy; (3) coarse sand with confined water, the pressure water level is 2.0 m above ground level. Is there any danger of uplift at the bottom of the excavation? If the foundation is buried deep, in addition to lowering the water level below the middle sand layer to the bottom of the pit, it is necessary to try to reduce the pressure level in the coarse sand by a few meters. (1) the base of the foundation excavation is 1 m and the strength layer is the middle sand layer Total coverage pressure of the soil above the top of the confined aquifer: 20 x 1 + 19 x 2 = 58kPa Water pressure at the top of the confined aquifer: 10 x (2 + 2 + 2) = 60kPa Because 58 60 so there is a danger of uplift at the bottom of the pit! (2) the base depth is 1.5m Total coverage pressure of the soil above the top of the confined aquifer: 20 x 0.5 + 19 x 2 = 48kPa Water pressure at the top of the confined aquifer = 10 times: 4.8 m or less; Therefore, the pressure level should be reduced by 6-4.8 = 1.2 m. 2-2 end of a strip footing b = 1.8 m wide, depth d = 1.2 m, the foundation soil is clay, Angle of internal friction values = 20 °, the cohesive force of standard value = 12 kpa, underground water level and the basal level, severe soil effectively, and the basal above soil severely. Determine the bearing capacity characteristic value of foundation. In this paper, the formula of the bearing capacity of the foundation can be determined by using the canonical recommendation theory formula. By = 20 ° look-up table 2-3, due to the basement and ground water level, therefore take effective severely, therefore, characteristic value of subgrade bearing capacity 2-3 a base width of 2m, buried depth of 1m. The foundation soil is medium sand, and its severe is 18kN/m3, and