STUDY OF FLOOR HEAVE IN SOFT ROADWAY

A sump of a certain coal mine at -400m level is located in a complicated geological structure zone and its floor strata have a very high dilatability when encountered by water. Under high tectonic stress, high in-situ stress and high expansion stress, previous common anchoring-netting-shotcreting and pre-stressed cabling support can not at all keep its indispensable stability of surrounding rock in the sump. Based on the analysis of in-situ geological conditions and surrounding rock failure reasons, and combined with the shortcomings of previous support design, a full-face reinforced concrete arch walling approach was adopted for the sump support. A kind of long distance pumping concrete technology was used in the concrete arch walling support, which fetched up the shortages of common manual arch walling. Good technical effects and economic benefits were obtained. The research results show that it is very difficult to keep the stability of sump in soft surrounding rock with great expansively only through anchoring-netting-shotcreting and pre-stressed cabling support. It can improve the loading capability and integrity of support structure effectively through grouting for large broken zone of surrounding rock. The support structure formed by full-face reinforced concrete arch walling can control the heavy floor heave of roadways effectively.