Abstract: Closed diaphragm walls, when serving as long-term foundations, demonstrate exceptional lateral bearing capacity. Relying on a specific project in Shenzhen, a lateral static loading test is conducted on enclosed rock-socketed diaphragm walls. The test monitors the displacements at the wall top and lateral geotechnical resistance using pre-installed instruments. During the experiment, the maximum applied load reached 80500 kN, representing the largest lateral static loading test conducted globally to date. The experimental results reveal that the load-displacement curve of the rock-socketed closed diaphragm wall exhibits gradual and nonlinear characteristics. Throughout the loading process, the wall experiences both horizontal and vertical rotations, with horizontal rotation primarily caused by the uneven distribution of rock layers on-site. The lateral geotechnical pressure with depth shows a trend of initially increasing and subsequently decreasing, with the maximum pressure observed at a depth of 0.28 times the wall depth. The distribution of lateral geotechnical pressure was significantly influenced by the position of the vertical rotation point, which is located in a relatively shallow rock layer. Furthermore, no resistance is provided by the enclosed soil, and the enclosed rock resistance is signlficantly reduced compared with the surrounding rock resistance. Specifically, the enclosed rock resistance of moderately weathered granite is approximately 0.73 times that of the surrounding rock, while the enclosed rock resistance of slightly weathered granite is approximately 0.63 times that of the surrounding rock.