發(fā)布時間：2018-10-09 15:35

【摘要】：現(xiàn)代地下工程支護(hù)結(jié)構(gòu)設(shè)計的基本指導(dǎo)思想是按照"新奧法"原理,強(qiáng)調(diào)通過適時加固圍巖,使得圍巖成為承載結(jié)構(gòu)的主體。但是對于支護(hù)時機(jī)的掌握,目前仍然缺乏可靠的理論和公式的指導(dǎo),只能根據(jù)現(xiàn)場監(jiān)測信息和經(jīng)驗(yàn)判斷來確定。提出脆性圍巖的"適時支護(hù)",是指在圍巖達(dá)到彈性極限應(yīng)變而破壞之前進(jìn)行支護(hù),即在時效變形作用下,圍巖應(yīng)力處于本構(gòu)關(guān)系彈性段后段,但是還沒有進(jìn)入軟化的非穩(wěn)定段。基于這一思想以及地下工程時效變形特征,提出了最優(yōu)支護(hù)時機(jī)的近似計算公式。研究表明:最優(yōu)支護(hù)時機(jī)與圍巖收斂時間、圍巖強(qiáng)度應(yīng)力比、開挖后應(yīng)力以及支護(hù)圍壓相關(guān)。由于圍巖應(yīng)力處處不同,可以由公式計算得到頂拱、邊墻等不同部位的最優(yōu)支護(hù)時機(jī),從而指導(dǎo)支護(hù)設(shè)計。研究對長期困擾地下工程界的脆性圍巖最優(yōu)支護(hù)時機(jī)問題提出了一種理論方法。
[Abstract]:According to the principle of "New Austrian method", the basic guiding idea of modern underground engineering supporting structure design is to strengthen the surrounding rock in time and make the surrounding rock become the main body of the bearing structure. However, there is still a lack of reliable theory and formula to guide the timing of support, which can only be determined by field monitoring information and empirical judgment. It is put forward that the "timely support" of brittle surrounding rock means that the surrounding rock is supported before the rock reaches the elastic limit strain, that is, under the action of aging deformation, the stress of surrounding rock is in the back of the elastic segment of constitutive relation, but it has not entered the unsteady section of softening. Based on this idea and the time-dependent deformation characteristics of underground engineering, an approximate formula for calculating the optimal supporting time is put forward. The results show that the optimal supporting time is related to the convergence time of surrounding rock, the ratio of strength and stress of surrounding rock, the stress after excavation and the confining pressure of support. Because the stress of surrounding rock is different everywhere, the optimal supporting time of different parts such as top arch and side wall can be obtained by formula calculation, so as to guide the design of support. In this paper, a theoretical method is proposed to solve the problem of the optimal supporting time of brittle surrounding rock, which has been puzzling the underground engineering circle for a long time.
【作者單位】： 四川大學(xué)水利水電學(xué)院水力學(xué)及山區(qū)河流開發(fā)與保護(hù)國家重點(diǎn)實(shí)驗(yàn)室;中國電建集團(tuán)成都勘測設(shè)計研究院有限公司;四川大學(xué)災(zāi)后重建與管理學(xué)院;
【分類號】：TU45
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本文編號：2259854