摘要
///Bored piles for foundation of high buildings are common in China. In order to meet the requirements of construction design, bearing stratum of bored piles is required to be comparatively intact rocks or cobble layers with high bearing capacity. Piles with great length and big size increase the cost ratio of whole subgrade construction and difficulties in construction. At a construction site in Weinan City, bored piles with a diameter of 600 mm and a length of 30 m were used in subgrade construction, which couldn’t reach the requirements of load-bearing capacity above. Post pressure grouting of borehole is adopted for increasing side friction of piles and bearing capacity at pile ends, which could enhance the load-bearing capacity of subgrade piles and reduced the possibility of subsidence of subgrade piles.