冻结法凿井冻结壁内外部冻胀力的工程实测及分析

在郭屯矿、郓城矿冻结法凿井过程中,开展了冻结壁内、外部水平地压的现场实测研究.结果表明:地层冻结过程中,冻结壁内、外部产生了极其显著的水平冻胀力;最大冻胀力达到初始水平地压的0.8～1.23倍,普遍介于0.9～1.1倍之间;导致冻结壁外载最大达到甚至超过初始水平地压的2倍.井筒掘进过程中,冻胀力发生了不同程度的释放,冻结壁外部残余冻胀力约为最大冻胀力的0.45～0.60倍,使冻结壁外载约为初始水平地压的1.5倍.冻胀力的积聚与释放,加剧了井筒掘砌过程中冻结管与冻结壁的受力与变形,并使冻结压力接近甚至超过初始水平地压,是威胁冻结凿井安全的关键因素.

In-Situ Measurements and Analysis of Frost-Heave Pressure Inside and Outside the Ice Wall During Freeze Sinking

In-situ measurements of horizontal ground pressure were made both inside and out-side the ice wall during freeze sinking in the Guotun and the Yuncheng coal mines. The results show that significant frost-heave pressures arose inside and outside the ice wall during ground freezing.The maximum horizontal frost-heave pressure reached 0.8-1.23 times (more fre-quently 0.9-1.1 times) the initial horizontal ground pressure. As a result, the maximum hor-izontal load on the ice wall reached, or even exceeded, twice the initial horizontal ground pres-sure. The frost-heave pressure was reduced to 0.45-0.60 times the maximum value during shaft sinking. The horizontal load on the ice wall still remained 1.5 times the initial horizontal ground pressure. Accumulation and discharge of frost-heave pressure will markedly increase the stress and deformation of the ice wall and the freezing pipes. The pressure induced in the ice wall may approach, or even exceed, the initial horizontal ground pressure, which is an key factor that threatens safety during freeze sinking.