TEST STUDY ON ANCHORAGE FORCE OF PRESTRESSED ANCHOR CABLES FOR FOUNDATION PIT
基坑工程预应力锚索锚固力试验研究

There are many influence factors on anchorage force of prestressed anchor cables for foundation pit.The main influence factors are physico-mechanical properties of rocks and soils in anchorage area,the construction technological process of anchor cables,and loss of prestress in locking anchors,etc..Based on engineering tests,it is analyzed that the tension force of each anchor cable is distributed unevenly.There are two causes for this phenomenon:(1) acted by the gravity,the jack axis deviates from the axis of prestressed anchors;(2) because of the error between construction angle and design angle of drilling hole,the prestressed anchor cables is not vertical to the anchorage block.The loss of prestress is discussed in single tension locking and cycle tension lockinga,nd continuous monitoring of anchorage force is described in deep excavation.The acceptance test criteria for pulling resistance are discussed,the simplified calculation method of elastic deformation of prestressed anchor cable is presented;and a revised proposal is put forward.Three indices such as total displacement,increment displacement by each grade load and percentage of rebound should be considered in the acceptance test for pulling resistance of anchor cables.