(中南大學(xué) 資源與安全工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 水和加載條件對(duì)巖石材料的強(qiáng)度有很大的影響，但高應(yīng)變率下飽水巖石的動(dòng)態(tài)特性研究仍十分缺乏。通過(guò)對(duì)干燥和飽水砂巖進(jìn)行壓縮試驗(yàn)，發(fā)現(xiàn):干燥和飽水砂巖的動(dòng)態(tài)壓縮強(qiáng)度都隨著應(yīng)變率的增加而增大，且飽水巖石表現(xiàn)出更強(qiáng)的率相關(guān)性。引入干燥巖石強(qiáng)度與飽水巖石強(qiáng)度的比值(水影響因子WAF)來(lái)描述不同應(yīng)變率下水對(duì)巖石壓縮強(qiáng)度的影響。在靜態(tài)壓縮條件下WAF約為1.38，隨著應(yīng)變率的增加WAF不斷減小。當(dāng)應(yīng)變率達(dá)到190 s-1時(shí)，WAF減小至0.98，表明高應(yīng)力率時(shí)飽水巖石的壓縮強(qiáng)度可以大于干燥巖石的壓縮強(qiáng)度。進(jìn)而，基于滑移裂紋模型，討論了水和應(yīng)變率對(duì)巖石特性的雙重影響，為實(shí)驗(yàn)結(jié)果提供了較好解釋。
關(guān)鍵字: 巖石；強(qiáng)度；應(yīng)變率；飽水巖石
（School of Resources and Safety Engineering, Central South University, Changsha 410083, China）
Abstract:The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and saturated sandstone specimens, it was found that the dynamic compressive strength of both dry and saturated sandstone specimens increased with the increase of strain rates. The saturated rock specimens showed stronger rate dependence than the dry ones. The water affecting factor (WAF), as the ratio of the strength under dry state to that under saturated state, was introduced to describe the influence of water on the compressive strength at different strain rates. The WAF under static load was close to 1.38, and decreased with the increase of strain rate. When the strain rate reached 190 s-1, the WAF reduced to 0.98. It indicates that the compressive strength of saturated specimens can be higher than that of dry ones when the strain rate is high enough. Furthermore, the dual effects of water and strain rate on the strength of rock were discussed based on sliding crack model, which provided a good explanation for the experimental results.
Key words: rock; strength; strain rate; saturated rock
