# Enlarged Head Pressure-Dispersed Anchor Cable for Foundation Pit Engineering Purposes
## 1 Introduction  
During construction of foundation pits, the unpredictability of the seepage and deep environment increases the difficulty of rock-soil anchoring technology. At present, the tension anchor cable is widely used in foundation pit engineering. During the application process, the grout-soil interface gradually exhibits a \"debonding\", blindly improving the anchoring length, which not only occupies the outer space of the property line, but also makes the anchoring effect less obvious. At present, many scholars have made remarkable achievements in research on tension anchor cables. In terms of engineering tests and indoor model test research, [PERSON] et al. [1] put forward the concept of \"end pressure inflection point\". Through the analysis of several engineering examples, it was concluded that the buried depth of the anchor solid, cohesion of the soil body, and internal friction angle were the main factors affecting end resistance. In the tension test of the tension-type enlarged head anchor cable, [PERSON] et al. [2] found that the displacement of the anchor cable determined the degree of exertion of the lateral resistance through the study of anchor failure. [PERSON] et al. [3] studied the mechanism and phenomena of the interaction of the anchor soil and showed that the shear-induced soil dilation was the main factor leading to increased friction at the interface of the anchor soil. [PERSON] et al. [4] found that \"constant resistance\" and \"elongation\" are the two most important indicators to evaluate the performance of anchor cables. [PERSON] et al. [5] found in a field experiment that soil mass at the front end of a pressure type anchor cable with enlarged head provides important uplift resistance. In terms of anchor tensioning. [PERSON] et al. [6] found that the tensioning sequence of anchors can follow the principle of a certain distance between tensions in reducing the loss of axial force of anchors. [PERSON] et al. [7]optimized the calculation method of the geotechnical model and evaluated this method through minislump test. Using numerical simulation research, [PERSON] et al. [8] solved the stress characteristics of the enlarged head anchor rod under different structural parameters and deformation of the surrounding soil layer and its influence on the vertical displacement of the anchor rod using the finite element analysis software ABAQUS. It was observed that the length of anchorage section increased, and its horizontal displacement decreased gradually, which then tends to be stable. Increasing the diameter of the anchor section reduced the degree of deformation of the surrounding soil layer, and the axial force of the anchor rod decreases slowly. [PERSON] [9] investigated the anchoring mechanism and found that the axial value of the anchor solid was large at the top, and the force decayed rapidly along with the depth of the anchor cable. In addition, the shear stress curve showed an exponential function distribution along with the interface of the anchor solid. [PERSON] et al. [10] proposed a new type of support structure that could withstand the transverse shear force. The numerical results showed that the surface displacement was reduced by at least 20%, and the equilibrium time was shortened compared with the original scheme. [PERSON] et al. [11] studied the transverse shear force of the anchor cable. The numerical results showed that there were two boundary anchor lengths in the shear test of the anchor cable. [PERSON] [12] simulated the foundation pit excavation of the anchor pile support structure and studied the shear stress distribution law of the grout interface in the tension-dispersed anchor cable. The results showed that the peak shear stress of the anchor cable was about 1.5 times that of the tension-dispersed anchor cable. [PERSON] [13] proposed a finite element calculation model for the ground anchor and compared the numerical prediction with the observed measurements.