【摘要】：通過(guò)對(duì)水布埡筑壩堆石料進(jìn)行0.2~3.5 MPa圍壓下的大型三軸固結(jié)排水剪(CD)試驗(yàn),分析了不同圍壓下堆石料的偏應(yīng)力-軸應(yīng)變關(guān)系及體應(yīng)變-軸應(yīng)變關(guān)系的變化規(guī)律;引入破壞強(qiáng)度和體變與圍壓的關(guān)系,采用臨界偏應(yīng)力σ_(cre)和臨界體應(yīng)變?chǔ)臺(tái)(vcre)作為歸一化因子對(duì)不同圍壓下的應(yīng)力-應(yīng)變關(guān)系試驗(yàn)結(jié)果進(jìn)行歸一化處理,建立了不同圍壓下的應(yīng)力-應(yīng)變關(guān)系表達(dá)式,并將計(jì)算預(yù)測(cè)與試驗(yàn)結(jié)果進(jìn)行對(duì)比驗(yàn)證。研究表明:對(duì)于顆粒級(jí)配確定的密實(shí)堆石料,初始變形期存在一定的彈性增長(zhǎng)階段,且該直線段的斜率受圍壓的影響較大;低圍壓時(shí)表現(xiàn)為應(yīng)變軟化,先剪縮后剪脹為主的力學(xué)特性,且圍壓越低,剪脹效應(yīng)越明顯;高圍壓(0.8 MPa≤σ_3≤3.0 MPa)時(shí)表現(xiàn)為應(yīng)變硬化、剪縮為主的特性;剪脹消失的臨界圍壓處于0.45~0.8 MPa之間;超高圍壓(σ_33.0 MPa)條件下,雖表現(xiàn)為應(yīng)變軟化、剪縮的特性,但其應(yīng)變軟化的機(jī)制與低圍壓下不同;分析認(rèn)為,超高圍壓下剪切過(guò)程中顆粒的相對(duì)破碎率達(dá)15%以上,顆粒破碎引起的堆石料強(qiáng)度降低大于圍壓的增大對(duì)堆石料強(qiáng)度的提高。峰值主應(yīng)力比隨圍壓的增大而降低,且隨軸應(yīng)變的增大而趨于一致。堆石料的破壞強(qiáng)度與圍壓呈線性相關(guān)。最后,通過(guò)計(jì)算預(yù)測(cè)結(jié)果證明了該應(yīng)力-應(yīng)變關(guān)系表達(dá)式的正確性。
[Abstract]:Based on the large triaxial consolidation drainage shear (CD) test under the confining pressure of 0.2 ~ 3.5 MPa for the rockfill material of Shuibuya dam, the variation law of the deformation stress-axial strain relationship and the body-strain-axial strain relationship of the rockfill material under different confining pressures are analyzed. By introducing the relationship between failure strength, bulk deformation and confining pressure, the critical deflection stress 蟽 _ (cre) and critical bulk strain 蔚 _ (vcre) are used as normalized factors to normalize the stress-strain relation test results under different confining pressures. The expression of stress-strain relationship under different confining pressures is established, and the calculated prediction is compared with the experimental results. The results show that there is a certain elastic growth stage in the initial deformation period for the dense rockfill material determined by particle gradation, and the slope of the straight section is greatly affected by the confining pressure, while the strain softening occurs when the confining pressure is low. The shear expansion effect is more obvious with lower confining pressure (0.8 MPa 鈮，

本文編號(hào)：2189182