First, the supporting role of the pile body:pine wood pileThe composite foundation uses pine piles to replace the low-modulus, low-strength soil with the same volume as the pile body. When bearing external loads, the stress in the foundation is redistributed according to the pile-soil stress ratio.

The stress gradually concentrates on the pile body, and the stress borne by the soil around the pile decreases accordingly, and most of the load is borne by the pine piles.

Since the strength and deformation resistance of piles are better than those of soil, the bearing capacity and modulus of the formed composite foundation are also better than those of the original soil, thereby achieving the effect of reducing deformation and improving bearing capacity.

2 is the squeezing effect: When constructing pine wood piles, hammering is used to drive, and the original soil at the position of the pile hole is forced to be squeezed laterally, which increases the density of the soil layer within a certain range around the pile and plays a squeezing effect.

　　pine wood pileDuring construction, the composite foundation compacts the soil between the piles, making the soil between the piles dense, thereby increasing the bearing capacity of the soil between the piles and reducing the compressibility.

pine wood pileThe application on soft soil foundation is based on the practical experience of engineering construction on soft soil foundation. Engineering geological survey and geotechnical testing must be carefully carried out before the design of soft soil foundation. Only by ascertaining the soil layer and soil quality can the design be carried out correctly. and construction; in addition, we must start from the characteristics of the soil layer and soil quality of the site, comprehensively consider the structure, construction and use of the foundation and foundation, and rationally select the foundation treatment plan through comparison of plans.

Generally, when the thickness of soft soil is less than 5m, it is more suitable to use fir piles. In order to facilitate pile driving, the pile length should not exceed 4m. When making end-bearing piles, in order to ensure that the pile tip can enter the bearing layer, the upper part can be excavated to the burial depth of the foundation first. Then drive the pile. The material of the pile must be pine wood, because pine wood is rich in rosin, which can well prevent corrosion by groundwater and bacteria, and is relatively cheap.

　　pine wood pileIt is suitable for working below groundwater. It is not suitable to use fir piles in areas where the groundwater level changes greatly or the groundwater is highly corrosive.

Practice has proved that when short wooden piles are used to deal with weak foundations, they have the advantages of convenient construction and obvious economic benefits. They can avoid a large amount of earth excavation. Therefore, they are used in areas with abundant pine wood resources.pine wood pileIt is economically and technically feasible to deal with weak foundations, and it can be regarded as an effective means to deal with weak foundations.