Description
WCH4 is an innovative modular wireless instrument for cross-hole tests on foundation poles. System core are motorized reels electronically controlled on which are mounted hig-power borehole probes for cross-hole investigations on foundation poles, diaphrams, and all those infrastructural cement or concrete works that could be verified by cross-hole tests, that is through discent in tubes prepared at casting and subsequently filled by water. Each reel of WCH4 system integrates a motorized probe with cable 60 mt, and all control electronics which supervises automatic management of the probes during descent/ascent of probes (cross-hole) and saving data. Due to Rugged tablet and the almost complete absence of physical cabling, settings, measurement management, besides display and interpretation of acquired data, are easy and immediate. In direct analysis mode each wave emitted by the internal generator is fully displayed and moreover it’s possible to modify parameters of display to make even easier reading velocity through crossing and the possible presence of tested defective material. Through the use of 2-3-4 motorized reel with automatic and simultaneous movement, it’s possible to exponentially reduce survey time, because with one only descent/ascent of probes inside investigated pole (which has to be instrumented with 2-3-4 tubes) it’s possibe to obtain corresponding sections. Acquired data at every single pulse are displayed in real time on large monitor of the tablet, allowing immediate viewing of possible imperfection in the investigated structure. Executive procedure of cross-hole with 2-3-4 channels is managed with fully automated modes. Only operations required by user is the placement of encoder to read the position of the motorized probes on prepared tubes and the early alignment of the probes on pole head. Once concluded this operation, just push the key to start data acquisition which is automatically managed by the system. It’s possible to verify data as they are acquired in order to check in real time performance test. It’s also possible to immediately print test report with its data of the just run investigation directly on site. Cross-hole method of analysis on foundation poles of buildings and infrastructural works allows to perform an high resolution accurate and qualitative verification of investigated material, usually a foundation pole. An ultrasonic wave is sent from a transmitting to a receiver device, which are automatically guided from the instrument along total lenght of the pole entirely “drowned” during casting. Velocity of the sonic wave and its energy are strongly influenced by the quality of the cement. So, it’s possible to verify its features and provide a tomographic representation called diagraphy. In CROSS-HOLE tests on concrete pole (CLS), in order to obtain a right measurement of delay of the crossing wave and an optimal reception of the signal, it’s necessary to manage constant advancing of the probes, which is feasibile due to medium velocity indicators and measurement of depth displayed with a graphic on manual encoder which, in case of overcoming of medium parameteres, indicates what to do to return back in limits.
Reference standards: ASTM D6760-08
Methodologies
The cross-hole is a method to analyze the foundation poles of buildings that, with the use of ultra-sounds, crosshole, allow to carry out an accurate high resolution test. An ultra-sonic wave is sent from a transmitter to a receiver, which are convoyed automatically by the device along the entire length of the pole inside the pipes embedded inside of it, during casting. The speed of the sonic wave and its energy are strongly influenced by the quality of the cement. Therefore, it is possible to assess the characteristics and give a tomographic representation in 2D and 3D called diagraphy.
Technical Specifications
General
Wireless technology: WiFi – 2.4 GHz – 802.11b
Wireless synchronization: band 5 GHz, 8 selectable channels
Operating temperature: -20/+80 °C
Single unit dimensions: L220 x H225 x P250 mm
Reference legislation: ASTM D6760-08
Acquisition
Resolution: 12 bit
Time bases: 100ns, 200ns, 500ns, 1µs, 2µs, 5µs, 10µs, 20µs
Samples per event: 2048
Amplification factors: x1, x2, x4, x5, x8, x10, x16, x32
Bandwidth: 50 MHz
Ultrasonic filters: 50 Mhz
Differential error: <0.03%
Probes
Typology: Borehole
Frequency: frequency of resonance 52 kHz
Minimum excitation voltage: 500V
Miaximum excitation voltage: 2000V
Minimum step of measurement: 10 mm