Cement soil pile wall support technology is more often used in construction projects, in order to ensure the quality of construction, this technology needs to be constantly optimized and improved, but also combined with the actual situation of the construction project, using the principle of construction according to local conditions. The use of continuous cement pile wall can increase the stability of the slope of the building; the application of cement pile wall support technology can also avoid the collapse of the side soil. The reasonable use of machinery and equipment can speed up the rate of pile formation. The following author briefly introduces the practical application of cement pile wall support technology for reference.
1 cement soil pile wall support technology application requirements
1.1 Building materials
In the application of cement soil pile wall support technology in construction projects, first of all, we must choose suitable raw materials, in ordinary building construction, mostly used is ordinary silicate cement, using coarse or medium sand, and the mud content of not more than 5%, in the process of mixing will also use the coagulant and curing agent, these materials must have the inspection certificate, and also need to be tested at the scene to determine the relevant indicators, so as to To ensure the safety of building construction.
1.2 Mixing ratio
When using cement soil pile mixing technology, but also to control the ratio of raw materials, the general amount of cement mixing for the overall reinforcement of the weight of the soil pile 6-14%, reinforced 1 m 3 soil pile also mixed with 110-160kg of cement, water-cement ratio should be maintained at about 0.42-0.50. When cement mortar is used as the curing agent, it is also necessary to use sand and gravel, and in order to ensure the fluidity of the mixture, a certain proportion of calcium lignin sulfate is usually mixed.
1.3 Mechanical equipment
The application of cement soil pile wall support technology, also need to cooperate with the use of mechanical equipment, commonly used are: GZB-600 deep mixing equipment, mortar mixer, piling equipment, etc.; small tools include: tachometer, flow meter, guide frame, etc.
2 Site construction requirements
The construction site needs to be guaranteed to be flat and neat. The construction unit needs to clean up the construction site before entering the site, clear out all some obstacles, and also use clay to fill the low-lying position in the site, and then compact it.
In order to ensure the quality of construction, it is also necessary to determine the indicators of construction equipment, including the total amount of mixing equipment and pump body transportation, mixing time, lifting rate of cranes, etc. When mixing raw materials, it is also necessary to determine the matching ratio to ensure that all indicators meet the construction requirements.
2.3 Inspection and repair
When using machinery and equipment, in order to ensure the continuity of use, machinery and equipment should be overhauled in advance, and also carefully checked before entering the field to ensure the smoothness of the transport pipeline to avoid other unexpected situations in the process of construction.
3 Precautions for the application of cement pile wall support technology
In order to ensure the application of cement pile wall support technology, the construction unit needs to operate in accordance with certain processes, after the transport of machinery and equipment to the designated location, the first mixing of raw materials, check the sinking process; also configure the cement slurry, enhance the height of the slurry spray, and then mixing again; in the use of deep mixing equipment, but also constantly repeat mixing, lifting mixing; after removing the equipment from the construction site, the Need to do a good job of cleaning up.
After transporting the machinery and equipment to the construction site, the verticality of the frame of the mixer should also be adjusted, and after the mixer runs normally, the lifting equipment wire rope can be relaxed appropriately; the mixer is generally along the frame for cutting soil sinking mixing, the rate needs to be controlled at 80cm/min, in the process of mixing if it encounters hard soil, it will make the sinking rate lower, then the transport slurry pipe can be used to To make up water, so as to achieve the drilling requirements. After the mixer sinks to the specified depth, the mortar pump body can be opened for slurry spraying, the construction personnel need to control the height of the mixer, so that it generally rotates while spraying slurry, after stopping the slurry spraying, but also to discharge all the slurry in the aggregate hopper.
In the process of construction sometimes will attend the phenomenon of segregation, which greatly affects the quality of construction, the construction unit must do a good job of preventive measures, in lifting raw materials, should ensure the stability of the equipment, in accordance with the provisions of the control of the mixing rate and the number of times to ensure the uniformity and continuity of mixing. The construction unit should also control the grouting volume, and when encountering the sinking problem during the first mixing, it should not be flushed directly, but only after encountering the hard soil layer which causes the sinking rate to be reduced, the appropriate amount of flushing can be carried out. After the application of cement soil pile wall support technology, the equipment should also be flushed to avoid the problem of pipe blockage.
4 Cement soil pile wall support technology construction standards
4.1 Width and depth standard
The construction standard of cement soil pile wall support technology includes several aspects. When applying this technology, the construction personnel should first determine the standard of width and depth of the wall, and the value of width and depth of the wall is calculated based on the depth of the pit, construction soil environment and physical properties, ground load, environment, etc. In the clay soil environment, if the excavation depth of the pit is less than or equal to 5m, the depth value D=(0.7-1.1)h0 and the width value B=(0.5-0.7)h0 can be derived from experience, and the insertion depth can be slightly different between the front and rear rows.
4.2 Mixing ratio standard
When deep mixing equipment is applied to repeat mixing operation, the mixing ratio of cement is generally about 14-17% of solid soil density. When using powder spraying for deep mixing, the mixing ratio of cement is generally about 12-15% of the solid soil density. In order to better improve the rigidity of the cement soil wall, H-shaped reinforcement can be placed inside the mixing pile, which can not only improve its wall loading force, but also become a support wall structure with seepage resistance, generally applied in 8-10m deep pits with a cement mixing ratio of about 20%. In addition, when performing cement soil wall support technology, the high-pressure jet grouting pile method can be applied for operation. In order to ensure the effect of application, test spraying experiments will be conducted first to calculate the minimum diameter of the spray solid structure of different soil layers, high pressure construction technical parameters and other data, and the application of high pressure jet grouting pile method for construction, the water-cement ratio is generally controlled at about 1.0-1.4.
4.3 Foundation pit excavation standard
Application of cement pile wall support technology, need to ensure that the age of the foundation pit in more than 28d, when the strength of the foundation pit to meet the design requirements before it can be excavated. In the current society, there are more and more high-rise buildings and super high-rise buildings in the city, and the aesthetics of the buildings are getting stronger and stronger. In order to improve the utilization rate of land resources, the construction industry has also strengthened the use of underground space, and many buildings are equipped with basements, so when excavating the foundation pit, it is necessary to ensure the stability of the foundation, otherwise it will bring greater safety risks. Excavation of the foundation pit also needs to take into account the construction environment and understand the groundwater level of the construction site. Cement pile wall support technology can ensure that the wall can achieve the effect of retaining soil as well as seepage resistance, and it has the advantages of simple operation and convenient construction, and the raw materials used in construction are relatively small, which effectively reduces the cost, but there will be a larger problem of displacement, so in the process of deep foundation pit excavation, it is necessary to reasonably apply materials such as intermediate piers to control the displacement, so as to ensure the application effect of support technology.
Society is constantly progressing, construction projects are also increasing, the beauty of the building is getting stronger and stronger, in order to ensure the safety of the building use, the construction unit also needs to reasonably apply the construction technology. Cement pile wall support technology is an effective measure to ensure the stability of the building wall, in the application of this technology, the relevant system is more and more perfect, the building safety is also more and more high, which is conducive to ensuring the safety of people’s lives and property. This paper introduces the precautions for the application of cement pile wall support technology, and building construction units must combine the actual situation and reasonably apply this construction technology, so as to improve the overall construction quality of China’s construction industry.