Research on Comprehensive Prevention and Control Technology of Water Burst and Quicksand in Saturated Fine Sand Layer Tunnel
Because of the construction disturbance,the saturated fine sand is in a fluid-plastic state,and the water burst and quicksand are prone to occur when the tunnel is passed through,resulting in very high construction safety risks.Combined with the Baofeng tunnel project of Kunming-Hekou Railway,the section of the underpass expressway is located in the water-rich and saturated fine silt layer,which is a typical"rotten tunnel"with multiple gushes of water,sand and collapse.In order to ensure the normal operation of the highway and the safety of tunnel construction,the intelligent deep hole directional grouting and monitoring system is developed(patented).The comprehensive prevention and control technology of high pressure rotary jet pile with"double row of arch inserted into ϕ108 large pipe roof grouting+vertical grid at tunnel bottom+plinx on tunnel face+horizontal arch foot+diagonal lock foot"arrangement is adopted.At the same time,auxiliary water glass phosphate grouting is used to block sand and water after rotary spraying to form a water-bearing arch system,which ensures the stability of the tunnel surface and successfully solves the problems such as gushes of water,sand and collapse.Practice shows that:(1)the comprehensive control technical scheme of"high pressure rotary jet pile+large pipe roof+water glass phosphate grouting"has been successfully applied in the silty sand section;(2)the use of intelligent deep hole directional grouting and monitoring system enables the advance reinforcement to achieve the expected effects;(3)the key of the integrated control technology lies in the control of directional rotary jet,rotary withdrawal speed and grouting pressure.
tunnel engineeringwater burst and quicksandsaturated fine sandprevention and control technologyhigh pressure rotary jet pile
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