How to draw lines in foundation pit excavation

1, determine the slope coefficient according to the excavation depth and survey report.

2, according to the outside line of the foundation map, determine the working face, determine the slope starting line (groove bottom line) and gray line.

3. According to the excavation depth and slope coefficient, determine the horizontal distance of the slope (notch edge) and the grey line to complete the excavation sideline setting-out, and control the slope line at the bottom of the trench and the upper edge of the foundation trench during excavation.