Miniature static pressure gauge for monitoring settlement of soft soil roadbed of highway

Abstract

The invention discloses a miniature static pressure gauge for monitoring the settlement of a soft soil roadbed of a highway. The miniature static pressure gauge is characterized in that a shell is a sealed metal cylindrical cavity; a pressurizing ring is fixed at the center of a top cover of the shell; a dish-shaped film transversely separates the upper part of the shell, and the center of the dish-shaped film is fixed with the bottom of the pressurizing ring; the part, above the dish-shaped film, of the shell is connected with a corrugated pipe to be subjected to water injection, and the part, below the dish-shaped film, of the shell is provided with a frequency measurement system connected with the dish-shaped film; the frequency measurement system comprises a string wire, a vibration exciter, a cable and a frequency measurement instrument; the top end of string wire is connected with the center of the dish-shaped film, and the vibration exciter located on one side of the string wire is connected with the frequency measurement instrument on the ground through the cable penetrating through the side wall of the shell. Due to the arc-shaped curved surface of the dish-shaped film and the property of a large membrane surface, the miniature static pressure gauge can remarkably deform under a tiny pressure, so that the vibration frequency of the string wire is remarkably changed, and the change of the water outlet pressure can be accurately measured according to the change of the vibration frequency of the string wire so as to obtain the settling volume of a foundation; the miniature static pressure gauge has the advantages that the stabilization of the instrument is good, the measurement accuracy is high, and the field installation is easy.

Description

technical field [0001] The invention relates to a static pressure gauge, in particular to a static pressure gauge for monitoring foundation settlement. Background technique [0002] The settlement observation of the foundation is a key issue in the construction and operation of expressways. At present, there are three main methods for the settlement observation of the foundation: the settlement plate method, the section settlement tube method and the observation method based on the principle of liquid level difference (hydrostatic pressure difference). [0003] The device of the settling plate method is composed of a settling plate, a metal measuring rod and a protective casing. The settlement is observed by observing the elevation change of the metal measuring rod, but this method is easy to damage the metal measuring rod during the construction process, and the road near the settling plate should be separated. Construction, and the observation process and roadbed construct...

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Problems solved by technology

[0003] The device of the settling plate method is composed of a settling plate, a metal measuring rod and a protective casing. The settlement is observed by observing the elevation change of the metal measuring rod, but this method is easy to damage the metal measuring rod during the construction process, and the road near the settling plate should be separated. Construction, and the observation process and roadbed construction interfere with each other, increasing the workload and prolonging the construction period

[0004] The device of the profile settlement tube method is composed of an inclinometer, a horizontally placed inclinometer tube and a digital display. The inclination angle change of the position can be measured by the inclinometer to convert the settlement amount of the position. The disadvantage of this method is that the settlement When the inclinometer is large, the inclinometer tube is easy to break, and the guide groove with a fixed inclination direction in the inclinometer tube is prone to deflection when the roadbed is deformed, and the direction measured by the inclinometer will change accordingly, resulting in obvious errors. At the same time, the observation workload of this method Large and expensive to observe

However, judging from the existing use experience, since the subsidence of the foundation is often small, the water pressure transmitted to the embedded pressure sensor is also very small. It is difficult for conventional instruments to accurately measure the water pressure, and the observation error is large If high-sensitivity instruments are used to observe, not only the cost is high, but also the obtained data is prone to drift due to various accidental factors. These problems limit the use of the liquid level difference method in actual engineering

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