Ground Movement Induced by Installing MJS Column nearby Pumping Well

The soil displacement induced by installing the MJS column in complex geological conditions, such as nearby pumping well, has been not studied in detail. Based on a deep foundation pit of Shanghai, the ground surface vertical displacement, lateral and vertical displacements of subsoils induced by installing an MJS column adjacent to a pumping well were monitored. The drilling and sampling were conducted after the installation of the column between the MJS column and the pumping well. The monitored results indicate that during MJS installation, the ground surface was slightly uplifted, and the horizontal displacement was larger than vertical displacement. The 67% of the maximum horizontal displacement (32.86 mm) is induced by the pumping well, which is 1 m away from the nominal edge of the MJS column. The fine particle content of the soils surrounding the pumping well decrease after the pumping test and thus during the MJS installation, the high-pressure grout jet can easily erode these soils, which can obtain a larger column diameter and thus further lead to greater horizontal displacement of subsoils. Therefore, the lateral displacement induced by the installation of the MJS column adjacent to the pumping well should be noticed.