页岩气热解油基钻屑残渣路基填料的制备及其性能研究

Preparation and performance study on using shale gas oil-based drilling cuttings pyrolysis residue as subgrade filler

目的为探索页岩气热解油基钻屑残渣路基填料的可行性,采用石灰和粉煤灰作为复合材料,进行油基钻屑改性研究。方法比较不同矿物材料复配比例及掺量对改良残渣无侧限抗压强度和污染物浸出特性的影响效果,探究了残渣替代天然土的比例对改性路基填料击实特性和CBR值的影响规律。结果残渣固化后的无侧限抗压强度(7天)、CBR值分别可达3.93 MPa和15.5%,浸出液污染物均达到GB 8978-1996《污水综合排放标准》要求。结论复合矿物材料水化生成的水化硅酸钙、水化铝酸钙、氢氧化钙、碳酸钙和矿物材料自身均对重金属离子具有固化稳定作用,因此,对污染物可实施有效封堵和吸附,从而抑制污染物的浸出,同时可使固化体结构致密化,承载力得以提高,该体系具有良好的应用前景。

Objective In order to explore the feasibility of using shale gas oil-based drilling cuttings pyrolysis residue as sulograde filler,lime and fly ash were used as composite materials for modification.Methods The effects of different mixing ratio and dosages of mineral materials on unconfined compressive strength and leaching characteristics of solidified drilling cuttings were compared.Besides,the study was also conducted to investigate the influence of the incorporation ratio of pyrolysis residue to natural soil on compaction characteristics and CBR value of modified subgrade filler.Results 7-day unconfined compressive strength and CBR value can reach 3.95 MPa and 15.5%,respectively,and leaching characteristics of the solidified oil-based drilling cuttings pyrolysis residue could meet the requirements of GB 8978-1996 Integrated wastewater discharge standard.Conclusions The composite mineral materials themselves and their hydrated products including hydrated calcium silicate gel,hydrated calcium aluminate,calcium hydroxide,and calcium carbonate all have stabilizing effect on heavy metal ions from oil-based drilling cuttings.pyrolysis residue.Therefore,the composite mineral materials could not only densify the structure and enhance the bearing capacity of the solidified oil-based drilling cuttings pyrolysis residure,but also could effectively envelop and adsorb the contaminants so as to inhibit the leaching.Accordingly,the system exhibits good application prospects.