Pile body stress testing device of static-pressure high-strength pre-stress concrete pipe pile

Abstract

The invention belongs to the technical field of building construction stress testing equipment, and relates to a pile body stress testing device of a static-pressure high-strength pre-stress concrete pipe pile. A shallow groove is formed in the high-strength pre-stress concrete pipe pile in a cutting mode, an optical fiber Bragg grating sensor and an armored cable are in butt fusion and in series connection in a quasi-distributed mode, the optical fiber Bragg grating sensor and the armored cable which are in series connection are implanted into the shallow groove of the high-strength pre-stress concrete pipe pile and packaged and protected through epoxy resin mixed liquid, the optical fiber Bragg grating sensor is distributed at the position of the high-strength pre-stress concrete pipe pile according to the elevation of a soil layer needing to be tested, a pile body drilling hole is formed in the inner side of the top of the high-strength pre-stress concrete pipe pile, and the armoured cable is led out through the pile body drilling hole and is communicated with a data collecting system. The device is simple in structure, convenient to operate, high in measurement precision and sensitivity, strong in the capacity of resisting electromagnetic field interference and high in survival rate; compared with a traditional stress measurement element, the pile body stress testing device can easily achieve quasi-distributed and automatic monitoring.

Description

Technical field: [0001] The invention belongs to the technical field of stress testing equipment for building construction, and relates to a stress testing equipment for prefabricated pile piles constructed by the static pressure method in foundation and foundation engineering, in particular to a static pressure high-strength prestressed concrete pipe pile pile body stress testing device . Background technique: [0002] Concrete prefabricated piles, especially high-strength prestressed concrete (PHC) pipe piles, have the advantages of high bearing capacity, factory production, firmness and durability, fast construction speed, and can effectively save building materials and engineering costs. The vibration is small and has little impact on the surrounding environment. It is suitable for construction in urban areas, areas with sophisticated equipment and other areas with high requirements for the construction environment. Compared with hammering construction, the quasi-static ...

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Problems solved by technology

[0002] Concrete prefabricated piles, especially high-strength prestressed concrete (PHC) pipe piles, have the advantages of high bearing capacity, factory production, firmness and durability, fast construction speed, and can effectively save building materials and engineering costs. The vibration is small and has little impact on the surrounding environment. It is suitable for construction in urban areas, areas with sophisticated equipment and other areas with high requirements for the construction environment. Compared with hammering construction, the quasi-static pile pressure can ensure that the piles body integrity; compared with the large amount of waste mud produced by bored pile construction, static pressure pile construction is more environmentally friendly and pollution-free; most of the separation of static pressure pile sinking resistance is to obtain pile end resistance and pile side resistance through force-measuring elements Friction resistance, the force measuring element is easily affected by the test environment, so improving the survival rate of the force measuring element is the key to the success of the field test. For PHC pipe piles, attaching resistive strain gauges on the outside of the pile body is easy to be affected by the friction of the soil around the pile. If the pile is damaged, if the strain gauge is pasted inside the pile, it is not easy to operate due to the small inner diameter of the pipe pile, and the pipe cavity is easy to enter water, which is greatly affected by environmental factors, the accuracy is reduced, and the reliability and survival rate are not high; And vibrating wire steel bar stress gauge is stable, but the production process temperature of pipe pile is high, high temperature strain gauge is required, the cost is high and the survival rate is low; high-strength prestressed concrete pipe pile is different from square pile, steel pipe pile and other pile types , its own production process and characteristics have objectively caused difficulties in testing, and the processes of steel tensioning, pre-cast concrete, high-speed centrifugal rotation and high-temperature curing during the production process have caused great inconvenience to the pre-embedded force-measuring elements of the pile. Due to the thinness and weakness of the optical fiber, the sensor and transmission optical fiber must be carefully protected. The key to the success of in-situ monitoring of optical fiber sensing lies in how to realize the buried positioning of the sensor and ensure its survival rate in the extensive construction environment on site.

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