What kinds of retaining piles (walls) are there?
1, cement-soil deep mixing pile
Deep mixing cement-soil retaining wall is a kind of continuous overlapping cement-soil column and solid retaining wall. The deep mixing machine is used to forcibly mix the soil and input cement slurry on site.
Advantages: because there is no support in the general pit, it is convenient for mechanized rapid excavation; It has dual functions of retaining soil and stopping water; Generally more economical; No vibration, no noise, little pollution and slight soil squeezing during construction.
Disadvantages: the displacement and thickness are relatively large. For a long foundation pit, measures such as adding piers in the middle and arching should be taken to limit excessive displacement; Attention should be paid to prevent the surrounding environment from being affected during construction.
2. High pressure jet grouting pile
High-pressure jet grouting pile is also made of cement slurry, which is sprayed into the soil layer by rotating nozzle at high pressure, mixed with soil to form cement soil and solid, and superimposed with each other to form a pile for retaining soil and stopping water.
Advantages: the construction equipment has compact structure, small volume, strong maneuverability, less land occupation, little vibration of construction machines and tools and low noise, and will not bring vibration influence and noise pollution to surrounding buildings.
Disadvantages: a large amount of mud is discharged during construction, which is easy to cause pollution. This method is not suitable for strata with excessive groundwater velocity, frozen soil in karst areas without filler and soil with serious cement corrosion, because the sprayed slurry cannot solidify around grouting pipe.
3. Channel steel sheet pile
This is a simple steel sheet pile enclosure wall, which consists of front and rear buckles with overlapping or side-by-side channel steel. The channel steel is 6 ~ 8m long, and the model is determined by calculation.
Advantages: good durability and high secondary utilization rate; Convenient construction and short construction period.
Disadvantages: water and fine particles in the soil can not be stopped, and water isolation or precipitation measures should be taken in areas with high groundwater level; The bending capacity is weak, the support stiffness is small, and the deformation after excavation is large.
4, bored pile
Advantages: there are no environmental hazards such as vibration and noise during construction, no soil squeezing phenomenon, and little impact on the surrounding environment; The wall has high strength, high rigidity, good support stability and small deformation; When the engineering pile is also a cast-in-place pile, it can be constructed at the same time, which is beneficial to the construction organization and has a short construction period.
Disadvantages: the gap between piles is easy to cause soil erosion, especially in soft clay areas with high water level. According to the engineering conditions, construction measures such as grouting, cement mixing pile and jet grouting pile are adopted to solve the water retaining problem.
5. Water-resisting wall
Advantages: high rigidity and good water-stopping effect, and it is the strongest supporting type in the supporting structure.
Disadvantages: high cost and special equipment for construction.
6.SMW construction method
SMW construction method, also known as rigid cement-soil mixing pile method, is to insert H-beam (mostly H-beam, but also tensile steel sheet pile, steel pipe, etc.) into cement-soil pile. ) combine bearing with seepage prevention and water retaining to make it a retaining wall with both stress and seepage prevention functions.
There is basically no noise during construction, which has little impact on the surrounding environment; The structural strength is reliable and can be used in any occasion suitable for the application of cement-soil mixing piles; Good water retention and seepage prevention performance, no need to set up another water retaining curtain; Suitable for deep foundation pit with multi-point support; This method can replace the diaphragm wall as the underground enclosure structure under certain conditions. If certain construction measures can be taken, tensile materials such as H-beam can be successfully recovered; It is much lower than the diaphragm wall, so it has great development prospects.