Single-hole ultrasonic detection device for continuous integrity and rock entry depth of concrete diaphragm wall and method using the same

A single-hole ultrasonic detection method for continuous integrity and a rock entry depth of a concrete diaphragm wall, the single-hole ultrasonic detection method being carried out by a single-hole ultrasonic detection device,

• the single-hole ultrasonic detection device comprising:
• an apparatus host, an ultrasonic transducer and an ultrasonic signal feedback device, wherein the apparatus host is respectively connected to the ultrasonic transducer and the ultrasonic signal feedback device via a corresponding one of signal lines, the apparatus host is configured as an ultrasonic transmission and reception device, the ultrasonic transmission and reception device comprises an ultrasonic transmitter and an ultrasonic signal collector, the ultrasonic transmitter is configured to generate ultrasonic waves and the ultrasonic waves are transmitted via the ultrasonic transducer, the ultrasonic transducer is configured to collect and recover a reflected wave of the ultrasonic waves, convert signals of the reflected wave of the ultrasonic waves into electric signals, and send the electric signals back into the ultrasonic transmission and reception device, the ultrasonic signal feedback device performs analysis and calculation by identifying the reflected wave of the ultrasonic waves to obtain an acoustic impedance value of a target medium, so as to identify information of an encountered medium during a propagation of the ultrasonic waves;
• the single-hole ultrasonic detection method comprising:
• drilling an inspection hole on a top of the concrete diaphragm wall;
• injecting a conducting medium into the inspection hole to ensure that an interior of the inspection hole is fully filled with the conducting medium;
• connecting the apparatus host with the ultrasonic transducer and the ultrasonic signal feedback device respectively via the corresponding one of signal lines, and placing the ultrasonic transducer into the inspection hole slowly;
• marking scales on the signal lines previously by a tape, as lowering the ultrasonic transducer from an orifice to a bottom of the inspection hole;
• locating a ultrasonic flat probe, which comprised in the ultrasonic transducer, at a central position in the inspection hole, so as to ensure that an emission direction of the ultrasonic waves is perpendicular to a longitudinal axis of the concrete diaphragm wall;
• pausing the lowering once every 10-20 cm, performing excitation and identification of the ultrasonic waves, and calculating and analyzing the acoustic impedance value Zi of the target medium in each pause by means of the ultrasonic signal feedback device;
• and storing data after collecting the acoustic impedance value;
• calculating collected and reflected echo signals by the ultrasonic signal feedback device, and analyzing the acoustic impedance value Zi of the target medium in each pause, judging the continuity integrity of the concrete diaphragm wall based on a change of a sound pressure of a primary echo along with a change of the rock entry depth, and determining a position of a bedrock surface at a side of the concrete diaphragm wall based on whether a sound pressure of a secondary echo suddenly changes, determining a depth to a bottom of the concrete diaphragm wall based on whether to generate the secondary echo, and determining the continuous integrity and the rock entry depth of the concrete diaphragm wall;
• and
• importing the acoustic impedance value Zi of the target medium stored in the ultrasonic signal feedback device into an analysis software comprised in the ultrasonic signal feedback device, and performing a deep analysis by means of the analysis software.