Calculation Of Soil Stress On Holding Sheet Of Pile-anchor Retaining Structure Considering The Effect Of Arch Between Piles

The pile-anchor retaining structure system is often used in Chongqing area. For a long time, there is a conception about the transfer approach of soil pressure behind the pile-anchor retaining structure system that the pressure is applied on the holding sheet firstly, then transferred to the columns by the sheet, finally transferred to the form ground by the anchor. Based on observing several engineering practices, an assumption is put forward that there are unloading arches in the soil between the piles.In order to research the effect of soil arch, the author designs an indoor model and analyzes the result of the exam. After analyzing the soil stress, flexure moment data of central section of the sheet, and the flections data of two kinds of holding sheet models which are different on span, the paper gets the horizontal and vertical soil stress distribution rules and compares the result of the exam with calculating result of classic soil stress theory. The exam validates existence of the unloading arch. The difference between the result and the classic soil stress theory is due to the effect of unloading arch.At the same time, the paper also analyzes the soil stress variety rules when the load was applied on the surface of the soil. Through the analysis, we know the holding sheet that is overloaded represents totally different soil rules compared with rigidity wall. The soil stress variety will lessen when the depth of soil increases. The soil stress also varies in the horizontal direction. The stress is the largest in the center of the sheet and the least both ends.Based on the engineering practices and indoor model exams, and according to the distortion character of the holding sheet, the paper obtains that it is the distortion character of the holding sheet induces the forming of the unloading arch. On the effect of the unloading arch, the soil pressure behind the sheets is transferred to the columns. The sheets only support the soil pressure inside the arch.Combining the unloading arch theory and parallel walls theory, the paper analyzes stress state of the soil inside the arch and presents a formula in order to calculate the soil stress on the holding sheet. Comparing the exams results with the calculating results of the parallel walls theory, a suggestion is presented that the calculation of the soil stress on the holding sheet can use the parallel walls theory.