窄缝局部应力解除和窄缝弹性模量试验拓宽应用的研究

RESEARCH ON BROADENING APPLICATION OF SLIT LOCAL STRESS RELIEVING AND SLIT ELASTIC MODULUS TEST

在地下洞室稳定分析中,洞室横截面关键部位岩壁上的围岩应力状态是至关重要的,通常由地应力测量和计算分析得到。但地应力测量费工费时,尤其在高地应力地区地应力测量比较困难,不易获得可靠的地应力实测资料,因此在地下洞室稳定性分析中往往缺乏重要依据。而评价洞室稳定性关键性资料是它横截面上洞壁的围岩应力状态。建议在洞壁上采用窄缝局部应力解除法测量洞壁关键部位的应力状态,只要在洞壁待测部位凿3个以上不同方向的窄缝槽,测量由凿槽引起的变形,就可测定此洞壁关键部位上的二维应力状态。在现场窄缝法岩体弹模试验后,拓宽应用它的试验成果,也即在试验中,设想继续提高埋设在窄缝槽中压力钢枕的压力,直到它引起的位移抵消由凿槽引起的位移,测得假设的窄缝槽中垂线上法向应力,然后推求洞壁上围岩应力,作为由窄缝局部应力解除法测定的洞壁围岩应力的补充,并进行相互印证。在工程应用实例中获得较好的效果。

In the stability analysis of underground caverns,the stress state on key parts of surrounding rock of the cavern？s cross-section is essential,and it is obtained by the geostress measurement and analysis.The geostress measurement is time-consuming and costly,especially in the high geostress region,it is more difficult to obtain reliable measured data;therefore there is often lack of an important basis for the stability analysis of underground cavern.The critical information to evaluate cavern stability is stress state of the wall rock on the cross-section,so the stress state measurement adopting slit local stress relieving method on the key parts of the wall rock is suggested;the two-dimensional stress state on rock wall can be determined provided gouging of more than 3 narrow slots of different directions on the measured site and measuring the deformation caused by the gouge.After the slit rock elastic modulus test in the site,the test results are widely applied,i.e.continue improving pressure of steel pillow buried in the narrow slot in the test,until the displacement caused by it offsets the displacement caused by gouging narrow slot,hypothetical normal stress on perpendicular bisector of the narrow slot is measured;and then to calculate the wall stress of surrounding rock;as a supplement to the measured wall rock stress by slit local stress relieving method and confirm each other.Good result is obtained in the example of engineering application.