水工建筑物施工中的软基处理研究

水工建筑物施工中的软基处理研究

发表时间：2018-05-24T11:01:04.627Z 来源：《防护工程》2018年第2期作者：陈水胜朱李春杨北胜陈利雄令凡冯震华（通讯[导读] The hydraulic building is mainly a dam body. Because of the huge pressure, the construction personnel need to deal with the soft soil foundation strictly.

中国水产科学研究院南海水产研究所/农业部南海渔业资源环境科学观测实验站广东广州 510300

摘要：软土地基和硬土相比，具有较大含水量、较强压缩性、较大孔隙性、较强韧度等特点，同时透水性非常差。作为水工建筑物的地基，这种地基会造成沉降快、排水固结慢，稳定性差的现象发生，造成水工建筑物的质量不合格。因此，需要采取相关处理措施，提高水工建筑物的承载力和稳定性。

关键词：水工建筑物；施工；软基处理

Study on Soft Ji Treatment in Construction of Hydrographic Buildings

Summary：Compared with hard soil and soft soil, it has the characteristics of greater water content, stronger compressibility, greater porosity and toughness.At the same time, water permeability is very poor. As the foundation of hydraulic building, this foundation will cause fast settlement, slow consolidation of drainage and poor stability, resulting in unqualified quality of hydraulic building.Therefore, relevant measures should be taken to improve the bearing capacity and stability of hydraulic buildings.

Key words：Hydrographic buildings；Construction；Soft Ji

preface

The hydraulic building is mainly a dam body. Because of the huge pressure, the construction personnel need to deal with the soft soil foundation strictly.Because of the bad construction environment, construction personnel have developed a variety of methods to deal with soft foundation problems.Furthermore, the stability of the whole hydraulic building can meet the requirements of the design.

1 Policy responses

1.1 Land conversion

Land exchange is a common method in the construction of hydraulic engineering.Because the construction of the building is in the position of the river, the geological structure is usually soft clay or silt, etc.Therefore, in order to deal with soft foundation effectively, it is necessary to use soil conversion method and its construction method is relatively simple. In particular, the silt layer contained in the soft foundation is excavated by construction machinery, and then the new sand loam is replaced with the dredged mud pit until the design elevation is reached.In addition, it is also applicable to the construction process of too tight construction time, while encounter soft foundation.In order to ensure that the new soil can be effectively combined with the old soil after replacement, the construction personnel in the excavation, must be connected to the surface shavings, but also need the project master to formulate a supporting construction plan, that is, the main four steps, because the soft foundation is silt, so containing a lot of water, the construction personnel need to drain water before excavation.The second is to use construction machinery to dredge the silt out, but it is important to note that when the excavation to the holding layer, can stop, and in order to ensure that the new soil can be filled with the perfect connection with it later, in the excavation process, the interface surface needs to be shaved.Third, after replacing the filling, the construction machinery such as bulldozer will be rammed, generally by the construction machinery on the surface of the ground back and forth about 10 times. The final step is to ensure that the foundation structure can be stronger, but also to add soil into it.

1.2Pile Foundation Method

In the course of foundation construction, if the thickness of silt has already exceeded 4 meters, it needs to be treated by pile foundation method. However, before using this method, the construction personnel must first make a careful study of the geological structure and then make a specific construction plan to guide the construction.According to the thickness of silt, the authors mainly give some construction technology of pile foundation. First, when the silt thickness is about 4 meters, cement lime pile can be used to treat soft foundation.In addition, the method is beneficial to improve the anti-seepage force of the foundation. In addition, the method can enhance the anti-seepage strength of the foundation. The cement lime pile usually has a diameter of 400 mm and a distance of about 1.5 m per pile. To ensure that it can be effectively reinforced, the pitch should be adjusted appropriately with the diameter of the pile, followed by the need to continue ramming the prefab when the silt reaches a depth of about 6 M until the surrounding soil is free of squeezing. Now stop ramming deep.When the thickness is close to 10 meters, it is necessary to drill the same hole into the hard soil for grouting. I'm sorry. Finally, when the thickness of the silt is more than 10 meters, levitation pile is needed to increase the compactness of the silt and increase the bearing capacity. In addition, the following principles should be followed in determining pile length: the depth of the full section of the pile end into the holding layer should not be less than 2d for clay and silt, less than 1.5d for sand and less than 1d for gravel. When there is a weak underlying layer, the thickness of the hard holding layer below the pile foundation should not be less than 4d.

1.3 Optimization of structure

If a soft foundation is encountered during the processing of soft base, it is necessary to use the optimization method. This can solve this problem effectively. If the hydraulic building is smaller, the floor area of the foundation can be increased during construction, and the pressure of the foundation can be reduced.If the building is large, the empty box floor is required. This method mainly uses the relationship between physical force and pressure to realize the treatment of soft base, so it mainly lies in the construction of the base plate of the structure. In general, the design of the structure is a plate girder type structure, which controls the outer edge of the base plate, thus increasing the carrying capacity of the entire base plate. At the same time, horizontal and longitudinal girder structures are required in the middle of the base plate to reduce the weight of the entire base and slow down the sinking rate。In addition, there are many characteristics of this method, which can greatly improve the anti-skid capacity and bearing capacity of the foundation.

2 Anti-seepage solutions

2.1 To improve the anti-seepage property of dam body by treating soft foundation

In order to ensure the impermeability of the dam during construction, the soft foundation must be treated well.The construction personnel need to pay attention to the poor bearing capacity of the foundation, must ensure the stability of the weight of the dam, in the actual processing process can use advanced waterproof materials to deal with it.In the treatment method, the geotechnical film can be used to intercept the seepage, and then placed on the adjacent surface to achieve the purpose of impermeability. However, the