A Research On The Technique Of Arch Beam Applied In Deep Excavation

Since 1990s, deep excavations in urban have met many problems, which has caused many people to pay more attention to. Traditional techniques in deep excavations can't satisfy construction in modem urban both in the measure of calculation and of construction. Recently, the techniques in deep excavations have been improved greatly, which has used many new styles of structures and techniques.The idea of deep excavations traditionally rather pay more attention to stress than to deformation. Calculation often ignores deformation caused by excavation. The model of calculation such as the rule of ultimate balance and the rule of 1/2 supporting have defects in fact. Recent years, the idea has been changed. Code in Deep Excavation Techniques (JGJ 120-99) has introduced rule of elastic brace, which can reflect essence better.Another problem in deep excavation is space in construction is so limit. The bracing system should posses little space as possible, which construction should be considered to improve efficiency to gain more profits.In the article, the author states the present situation in deep excavation and analyses the form of earth force, water force, model of calculation and deformation caused by excavating. In details, the author introduces a new technique, which is called circular beams bracing system in deep excavation, states the steps of calculation, construction and inspect. The author also gives a case to analyze the difference between theory calculation and realistic positions. The technique introduced in the paper should be referred to establishment of construction.