A Space-Time-Dependant Design Method and the Stability of Ice Wall for Deep Shafts

Abstract

The mechanical properties of artificial frozen soils are the key for application of artificial ground freezing, (AGF) especially the creep characteristics of artificial frozen clay when a deep shaft is sunk by using AGF. Many catastrophic accidents took place in clay strata in deep freezing shafts past because of freezing tube breaking and flooding through ice wall caused by large creep deformation of ice wall. A new creep constitutive equation with separated variables for artificial frozen clay, after C. C. Vialov, is presented on base of testing data of most kinds of artificial frozen clay under the condition of drained system. On base of the new equation, a space-time- dependant design method, a modified C. C. Vialov’s, is proposed and has been successfully used for ice wall of deep shafts all over China since 1996. Finally, the stability of ice wall for deep shafts can economically and efficiently be controlled by adjusting the variables of temperature T, un-supported height h and time elapsed t according to their sensitivity or influence.

Study on the mechanical properties and acoustic emission signal characteristics of freezing pipe

“…While the continuous improvement of construction methods and the emergence of new technological solutions have facilitated the expansion of many domestic underground projects (Han et al, 2023), including artificial ground freezing techniques, the phenomenon of freezing pipe fractures in freeze well freezing has been temporarily brought under effective control. However, due to the lag in freeze technology theory, coupled with the increase in freeze circle diameter and the widespread adoption of multi-circle freeze schemes, a significant resurgence of freezing pipe fracture accidents has emerged once again (Sheng, 2009;Chen, 2012).…”