Development of a vertical accuracy REAL-TIME monitoring system for columnar ground improvement

In ground improvement works underground, if the auger trajectory deviates from the correct position, there is a risk that not only the final shape but also the intended purposes of ground improvement such as bearing capacity, deformation control, and water shielding may not be achieved. Therefore, ensuring vertical accuracy is a crucial challenge. However, the current commonly used method for managing vertical accuracy assumes the rod to be always rigid and is controlled using inclinometers on the construction machinery above ground, making it unclear what the actual position of the rod tip underground is. To address this issue, a system has been developed to monitor vertical accuracy in real-time during construction by combining a gyro sensor with a wireless communication pipe. In this development, a gyro sensor is installed near the mixing blade at the end of the rod, and the sensor is connected to the surface using a dedicated wireless communication pipe. This allows for real-time measurement of vertical accuracy during construction and its incorporation into the construction process. This report applies the developed system to a 2-axis deep mixing machine and demonstrates the effectiveness of the developed system by comparing the real-time vertical accuracy obtained during construction with the actual measured vertical accuracy of the rod position after bottoming of the ground improvement.