西域组钙质胶结砾岩物质构成试验研究

Experimental study on material composition of Xiyu Formation calcareous cementitious conglomerate

西域组砾岩的物质构成较为复杂,目前对其试验研究较少。以分析西域组钙质胶结砾岩的物质构成为目标,通过酸化浸泡试验和CAD断面统计方法,并结合气体收集方法,来对西域组钙质胶结砾岩的物质构成进行初步的试验研究,运用两种不同比例盐酸溶液对砾岩试样的颗粒级配进行酸化试验分析。结果表明:经过1∶1盐酸溶液浸泡后<0. 075 mm粒径损失较大,1∶4盐酸溶液浸泡后试验结果较为理想;酸化分离筛分和CAD断面统计粒径含量结果基本一致;西域组钙质胶结砾岩碳酸盐含量为70%～80%,其余20%为碎屑物质和填隙物;碎屑物质中粒径> 2 mm的砾石平均含量为65. 2%,粒径2～0. 075 mm的砂平均含量为13. 2%,粒径<0. 075 mm的细粒平均含量为21. 6%。通过试验还发现钙质胶结砾岩中存在有某些物质与盐酸发生了反应,对试验结果产生了一定的影响。

The material composition of Xiyu Formation calcareous cementitious conglomerate is relatively complicated and few experimental studies are made on it at present.Taking the material composition of Xiyu Formation calcareous cementitious conglomerate as the study objective,a preliminary experimental study is made through acidification soaking experiment and CAD cross-section statistical method in combination with gas collection method,in which the acidification experiment analysis on the particle gradation of the conglomerate specimen is made with the hydrochloric acid solutions with two different proportions.The result shows that the loss of the particle size of<0.075 mm is larger after soaking in the hydrochloric acid solution of 1∶1,while the experiment result from the soaking in the hydrochloric acid solution of 1∶4 is more ideal.The results of the particle size contents from the acidification separation and screening and the CAD statistics are basically coincided.The carbonate content of calcareous cementitious conglomerate in the Xiyu Formation is 70%~80%with the other 20%of detrital material and interstitial matter.The mean content of the gravel with the particle size of >2mm in the detrital material is 65.2%,the mean content of the sand with the particle size of 2~0.075 mm is 13.2%and the mean content of the fine particle with the particle size of<0.075 mm is 21.6%.Through the experiment,it is also found out that some substances in the calcareous cementitious conglomerate react with hydrochloric acid with a certain impact on the experiment result.