# Model Test on the Behaviors of Deep Excavation with Lateral Confined Water
## 1 Introduction
### Model Test Monitoring  
Considering that the excavation response in the model test can be approximated as a plane strain problem [17], a monitoring profile was set at the middle section along the length of the excavation. The specific monitoring parameters include: lateral pressure, bending moment and horizontal displacement of diaphragm wall, pore water pressure, strut axial force and surface vertical displacement. The arrangement of the monitoring points is shown in Figure 6. Earth pressure cells are denoted by the letter \"E\", pore water pressure transducers are denoted by the letter \"P\", strain gauges on the diaphragm wall are represented by \"SD\", strain gauges on the struts are indicated by \"SS\", \"L\" and \"R\" represent the left and right sides of the excavation, respectively, and \"I\" and \"U\" represent the inside and outside of the excavation, respectively.  
Diaphragm wall lateral pressures were measured using strain-type earth pressure cells (DMTY, Nanjing Danmo Electronic Technology Co., Ltd., Nanjing, China) with a range of 20 kPa. These earth pressure cells were symmetrically placed along the diaphragm wall on both sides of the excavation. Seven earth pressure cells were installed outside the excavation along the depth direction, and three were placed symmetrically at the same depth as the outside, beneath the excavation floor. The vertical spacing between the pressure cells was 80 mm. The diaphragm wall bending moment was measured using strain gauges (BE-120-5 AA, Aviation Industry Corporation of China, Electric Measurement Instruments Co., Ltd., Xi'an, China). The bending moment results were calculated based on the small strain theory for elastic beams. Strain gauges were symmetrically arranged along both sides of the diaphragm wall, with a vertical spacing of 80 mm. The pore water pressure within the soil was monitored using miniature pore pressure gauges (DMKY, Nanjing Danmo Electronic Technology Co., Ltd., Nanjing, China) with a range of 30 kPa. The pore pressure gauges were symmetrically placed on both sides of the excavation. Five gauges were arranged along the depth at a distance of 70 mm from the excavation outside, and two were positioned 70 mm from the diaphragm wall at the excavation base, with a vertical spacing of 120 mm between them. The strut axial force was measured using strain gauges (BE-120-5 AA, Aviation Industry Corporation of China, Electric Measurement Instruments Co., Ltd., Xi'an, China). One strain gauge was installed on each of the four struts, positioned from top to bottom. For monitoring diaphragm wall horizontal displacement, two methods were employed: a laser rangefinder (D2-100m, Delixi Group Co., Ltd., Wenzhou, China) and a  
Figure 6: Location of monitoring points for model test.  
dial gauge (543-470B, Suzhou Quantum Instruments Co., Ltd., Suzhou, China). During excavation, the horizontal displacement of the diaphragm wall above the excavation surface was measured using the laser rangefinder, with five monitoring points placed along the depth: at 0 mm, 50 mm, 100 mm, 150 mm, and 200 mm depths. Dial gauges were placed at the top of the diaphragm wall on both sides of the excavation to monitor horizontal displacement at these locations. At a depth of 275 mm on both sides of the diaphragm wall, displacement meters (YWD, Liyang Jincheng Testing Instruments Co., Ltd., Liyang, China) were symmetrically placed to monitor real-time horizontal displacement variations. The vertical displacement of the ground surface outside the excavation was monitored using dial gauges (543-470B, Suzhou Quantum Instruments Co., Ltd., Suzhou, China). The dial gauges were symmetrically placed on both sides of the excavation at various distances from the diaphragm wall: 50 mm, 150 mm, 250 mm, 350 mm, and 450 mm.