1, geological conditions for digging piles
Digging pile foundation is suitable for soil layer and weathered soft rock layer without groundwater or with a small amount of groundwater.
2, the same pier digging pile construction sequence
The excavation sequence of each pile on the same pier depends on the stratum property, pile position arrangement and spacing. When the pile spacing is large and the stratum is dense, and blasting is not needed, oblique excavation can be carried out, otherwise single-hole excavation is appropriate. If the pile holes are arranged in a plum blossom shape, the middle hole should be dug first, and then other holes should be dug.
3, ventilation equipment setting points
When digging a hole, the hole wall must be supported. Always check the concentration of harmful gas in the hole. When the concentration of carbon dioxide exceeds 0.3%, other harmful gases exceed the allowable concentration or the hole depth exceeds 10m, ventilation equipment shall be provided.
4, hole blasting
Shallow hole blasting should be adopted for in-hole blasting. The drilling depth shall not exceed 0.4m for hard rock and 0.8m； for soft rock; The charge shall not exceed the hole depth of 1/3. Blasting in the hole should be initiated by electric fuse or nonel tube.
Before blasting, protective measures should be taken for the support near the hole. When the concrete strength of retaining wall does not reach 2.5MPa, blasting operation is not suitable.
The above is an introduction to the key points of digging pile foundation construction provided by Zhong Da Consulting for architects. For more knowledge of architectural terminology, please pay attention to the architectural knowledge column of Zhong Da Consulting.
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