Building engineering foundation Basics Technical disclosure of earthwork excavation construction
1) For excavation of various shallow foundations, if there is no sloping, the contour line of the groove edge shall be cut along the straight edge of the gray line first. (2) Excavation of various trenches and pits: a. shallow strip foundation. Generally, cohesive soil can be excavated in layers from top to bottom, and the depth of each layer should be 60 cm. The excavation shall be carried out in steps from the excavation end in reverse direction. Gravel soil shall be scarified with a pickaxe and excavated in a positive direction. The depth of each layer shall be determined according to the thickness of the turned soil. The bottom of each layer shall be cleaned and excavated, and then excavated gradually. b、 Shallow trench. The excavation of shallow strip foundation is basically the same, except that the trench wall is not cut, straight and leveled. The elevation shall be based on the size of the trench bottom from the top to the bottom of the gantry plate. When the excavation is close to the design elevation, 50 cm from the bottom elevation under the gantry plates at both ends shall be taken as the reference point. The elevation of the trench bottom shall be checked by drawing a small line with a ruler, and finally the trench bottom shall be trimmed. c、 When excavating the pit (groove) and pipe trench for grading, the slope shall be roughly excavated according to the slope specified in the construction plan, and then the slope line shall be made by layers according to the slope, one line shall be made every 3 meters, and the slope shall be shoveled based on this line. When deep pipe trench is excavated, a dumping platform with a width of about 80 cm shall be reserved in the middle of the trench wall. d、 When excavating a large area of shallow foundation pit, excavate along three sides of the pit at the same time. The excavated earthwork is loaded into a trolley or dumper and transported from the unexcavated side to the spoil site. 4. When the foundation pit (trench) or pipe trench is close to the underground water level, the excavation at the lowest elevation shall be completed first to facilitate centralized drainage. After excavation, when the excavation is within 50 cm from the bottom of the trench, the surveying and setting out personnel shall cooperate with the standard ruler rod that is 50 cm from the bottom of the trench, and level it with pegs at any time to check the elevation of the trench bottom. Finally, the pile shall be drawn from the axis (center line) at both ends to draw a line, check the size from the groove edge, determine the groove width standard, refuse to trim the groove side, and finally remove the earthwork at the groove bottom, trim the bottom and level it.
