1、外文原文：Analysis for interaction of supports and surrounding rock of gateways in longwall mingingWU Yong-ping(Xian University of Science and Technology, Xi an710054, China)Abstract:Gateway supporting in long-wall mining has been a problem that restricts the mine production and safety, the paper sets up
2、 an interaction model between support and surrounding rock (rock mass structure) and probes the elementary theory about ground pressure behaviors of gateway. Based on the analysis of supporting theories, some new viewpoints about gateways supporting and ground pressure controlling are put forward.Ke
3、ywords: support surrounding rock, interaction, gateway, long-wall miningIntroductionFor the gateways extracted in solid coal (rock) or having wide coal pillar in one side, the most unfavorable situation is to regard surrounding rock mass as loose medium, but even in this condition rock mass structur
4、e like arch can still form during a certain period, and its calculating theories is well-known.When the gateways of long-wall face are influenced by face advancing, in acute interval of working influenc zone (at the intersection region of face with gateways), because cover strata moves severely, the
5、 simple arch structure will be not formed in lower strata, but a 4-demensions rock structure which extends deeper and relatives with time- coal is formed. The structure can be described as formula (1) and has following characteristics:F (x, y, z, t) = 0 (1)(1) When gateways are ones driving along ad
6、jacent goaf or reserved for next face, the catch-borders of the structure will be solid coal one side of face, waste falling and compacted behind face and adjacent goaf, so its extending range will be very large.(2) The rock structure moves forward in the way of “forming -destabilizing forming again
7、 as the face advancing.(3) At the intersection of face with gateways, rock structure is regarded a flat cowl of its long axis along face line and short one along axial line of gateways.1. Analysis of internal stress of the rock structureSupposing t= t0 in formula (1) and the rock structure is shown
8、as Fig. 1.Getting any element from the model shown in Fig. 2, the distribution of its internal stress are shown as Fig. 1, and the equilibrium differential equation of the element can be obtained from Fig. 2.Fig.1 model of rock structure in gatewaywhere, Nx, Ny, Sxy, Syx are film internal stress; Mx
9、, My, Mxy, Qx, Qy are bending moments, twisting moments and shearing forces; q0 is uniform distributed load acting upon the rock structure coming from cover strata (upper strata); p0 is re-loading providing by supports in gateway.Fig.2 Mechanical model of elementAssuming curved surface equation of r
10、ock structure (as shown in Fig. 1) consists of two parabolic surfaces translating each other:.Then, maximum vector height of neutral surface is obtained, f=fa+fb, and its curvature and curve radii along x, y are separately:Where, fa, fb are separately vector heights of parabola of parallel rank xoz
11、and yoz.Analysis the rock structure using plate-cowl theories, we can obtain its internal stresses and displacements shown as follows: （2）And near board of x=0, x=a, its vertical displacements are:Its corresponding bending moments areSimilarly, bending moments near border y=0 and y=b also can be obt
12、ainedWhere, K1, K2, Ks, , , are factors of internal stresses relating with Thomsons function; E is elastic modulus of rock; h is cross-section thickness of structure (flat cowl); ， According to formula (2) (4), we can draw distribution states of internal stresses in rock structure as shown in Fig. 3
13、.Fig.3 Internal stresses distribution of rock structure2. Relation between the movement of rock structure and ground pressure behaviorBecause the coalface advances continuously, the deformation of the structure as (flat cowl) relates with time as formula(1)，so the damage of lower strata within range
14、 of structure extending increases gradually as time passing, which has been changing and overall strata of rock structure will change and which is a dynamic process in ground pressure behavior, from forming to its limiting equilibrium state of rock structure takes a period, so the velocity of face a
15、dvancing (speed of the structure moving) can have the moving characteristics of cover strata changed. When face advances very fast, the influence of ground pressure behavior of main roof (cover strata) acting upon rock structure will be decrease relatively (or influencing beside range of the structu
16、re) and it doesnt threaten gateway supporting. In addition, in lower strata within range of the structure extending, rock structure can t damage and deform at once because of face advancing fast, so loading of gateways surrounding rock will be reduced. On the contrary, if face advancing very slowly or stop advancing, range of the str
