深部巷道围岩复合注浆加固技术

Composite grouting reinforcement technology for deep roadway surrounding rock

针对深部巷道围岩复杂地质条件下单一注浆方式和注浆材料不能达到理想的注浆效果问题,提出了一种深部巷道围岩复合注浆加固技术。以山西某矿3210孤岛工作面为例,阐述了复合注浆加固技术原理及应用。首先,结合现场试验区域的地质力学测试结果、煤岩体物理力学参数等,计算3210回风巷各破裂区的范围;其次,基于围岩分区破裂特点,提出3步注浆工艺,即浅部低压渗透注浆、深部高压劈裂注浆和补充注浆,并根据各分区的范围确定3步注浆工艺中各个钻孔的深度;然后,根据各个分区中裂隙的发育程度和裂隙开度,选择相应的注浆材料:高渗透区宜采用无机水泥注浆材料,中等渗透区宜采用超细水泥注浆材料,低渗透区宜采用高分子化学浆液进行补注;最后,根据现场注浆试验,确定不同破裂区的注浆压力参数。采用注浆加固岩体锚固力、注浆加固岩体单轴抗压强度和围岩完整性3个指标综合判断3210回风巷注浆加固效果:采用复合注浆加固技术后,巷帮煤体锚固力提高144%,达到230kN;顶板和巷帮围岩单轴抗压强度分别增加10.9%和18.5%,分别达到50.68 MPa和23.37 MPa;巷帮煤体波速提高15.2%,达到750 m/s。从注浆区域与未注浆区域围岩变形速率和变形量来看,复合注浆加固技术取得了良好效果。

The single grouting method and grouting material can not achieve an ideal grouting effect under the complex geological conditions of deep roadway surrounding rock.In order to solve this problem,a composite grouting reinforcement technology for deep roadway surrounding rock is proposed.Taking the 3210 isolated island working face of a mine in Shanxi Province as an example,this paper expounds on the principle and application of the composite grouting reinforcement technology.Firstly,combined with the geomechanical test results of the field test area and the physical and mechanical parameters of coal and rock mass,the range of each cracked zone of 3210 return air roadway is calculated.Secondly,based on the crack characteristics of surrounding rock zones,three-step grouting technology is proposed.The technology includes shallow low-pressure infiltration grouting,deep high-pressure cracking grouting and supplementary grouting.The depth of each borehole in the three-step grouting technology is determined according to the scope of each zone.Then,the corresponding grouting materials are selected according to the crack development degree and crack opening scale in each zone.The inorganic cement grouting materials should be used in high permeability zones.The ultra-fine cement grouting materials should be used in medium permeability zones.The polymer chemical grouting materials should be used for supplementary grouting in low permeability zones.Finally,according to the field grouting test,the grouting pressure parameters of different crack zones are determined.The grouting reinforcement effect of 3210 return air roadway is comprehensively judged by using three indexes.The three indexes include the anchoring force of grouting reinforcement rock mass,the uniaxial compressive strength of grouting reinforcement rock mass,and the integrity of surrounding rock mass.After adopting the composite grouting reinforcement technology,the anchoring force of the roadway side coal body is increased by 144%,reaching 230 kN.The uniaxial compressive strengths of the roof and roadway surrounding rock increase by 10.9%and 18.5%respectively,reaching 50.68 MPa and 23.37 MPa respectively.The wave velocity of the roadway side coal body increases by 15.2%,reaching 750 m/s.From the deformation rate and deformation amount of surrounding rock in grouted area and ungrouted area,the composite grouting reinforcement technology has achieved a good effect.