岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
z2期
168-173
,共6页
干湿循环%力学特性%砂岩%本构模型%神经网络
榦濕循環%力學特性%砂巖%本構模型%神經網絡
간습순배%역학특성%사암%본구모형%신경망락
drying-wetting cycle%mechanical behavior%sandstone%constitutive model%neural network
基于不同干湿循环作用下砂岩单轴压缩试验结果，分析了干湿循环效应对砂岩变形、强度、破坏特征等力学特性的影响规律，认为随着干湿循环次数的增加，弹性模量及峰值强度均有降低的趋势，降低幅度先大后小，而且会以某一具体值为临界值发展变化，就本次试验而言为干湿循环20次时的抗压强度和弹性模量值；砂岩的破坏特征亦会受到干湿循环试验次数的影响，干湿次数越少，脆性破坏越明显，反之则延性特征增强，即砂岩会呈现一种从脆性到延性转化的破坏规律。以应变和干湿试验次数为输入层，应力为输出层，构建了2-12-1的三层神经网络本构模型。通过样本的学习与检验，证明该模型能较好地描述干湿循环作用下砂岩的力学性能，验证了利用神经网络方法建立岩石本构模型的可行性与可靠性。基于预测结果，建立了完整的考虑干湿循环效应的砂岩力学特性变化规律的数学函数关系式。
基于不同榦濕循環作用下砂巖單軸壓縮試驗結果，分析瞭榦濕循環效應對砂巖變形、彊度、破壞特徵等力學特性的影響規律，認為隨著榦濕循環次數的增加，彈性模量及峰值彊度均有降低的趨勢，降低幅度先大後小，而且會以某一具體值為臨界值髮展變化，就本次試驗而言為榦濕循環20次時的抗壓彊度和彈性模量值；砂巖的破壞特徵亦會受到榦濕循環試驗次數的影響，榦濕次數越少，脆性破壞越明顯，反之則延性特徵增彊，即砂巖會呈現一種從脆性到延性轉化的破壞規律。以應變和榦濕試驗次數為輸入層，應力為輸齣層，構建瞭2-12-1的三層神經網絡本構模型。通過樣本的學習與檢驗，證明該模型能較好地描述榦濕循環作用下砂巖的力學性能，驗證瞭利用神經網絡方法建立巖石本構模型的可行性與可靠性。基于預測結果，建立瞭完整的攷慮榦濕循環效應的砂巖力學特性變化規律的數學函數關繫式。
기우불동간습순배작용하사암단축압축시험결과，분석료간습순배효응대사암변형、강도、파배특정등역학특성적영향규률，인위수착간습순배차수적증가，탄성모량급봉치강도균유강저적추세，강저폭도선대후소，이차회이모일구체치위림계치발전변화，취본차시험이언위간습순배20차시적항압강도화탄성모량치；사암적파배특정역회수도간습순배시험차수적영향，간습차수월소，취성파배월명현，반지칙연성특정증강，즉사암회정현일충종취성도연성전화적파배규률。이응변화간습시험차수위수입층，응력위수출층，구건료2-12-1적삼층신경망락본구모형。통과양본적학습여검험，증명해모형능교호지묘술간습순배작용하사암적역학성능，험증료이용신경망락방법건립암석본구모형적가행성여가고성。기우예측결과，건립료완정적고필간습순배효응적사암역학특성변화규률적수학함수관계식。
Based on uniaxial compression test of sandstone under the different drying-wetting cycles, the laws of drying-wetting effect on mechanical behaviors of sandstone, such as deformation behavior, intensity behavior and failure characteristic, were analyzed. The results show that the elastic modulus and the peak strength of sandstone trend to decrease with the increase of drying-wetting cycles, and its reduction range is changed from large to small;moreover, the decrease of above data can not develop limitlessly but there is a constant value as critical value;in this test, the constant values of elastic modulus and the peak strength are experiment data of 20th drying-wetting cycles. The failure characteristic of sandstone is also affected by drying-wetting cycles, the less drying-wetting cycles are, the more obvious brittle damage is;that are, with the strengthen of drying-wetting effect, the damage law of sandstone present a transformation from brittleness to ductility. On the basis of these tests, taking the strain and drying-wetting cycles as input layer and the stress as output layer, the three layers neural network constitutive model, whose structure is 2-12-1, was proposed. Through the massive samples learned and inspected, the model can well describe the mechanical properties of sandstone under the cyclic drying-wetting effect, which also confirms that it is feasible and reliable for the neural network method to establish the rock constitutive model. At last, the intact function relations between the mechanical behavior and the cyclic drying-wetting effect were built.
