中国新纪录属种岩支蚁Cladomyrma scopulosa Eguchi&Bui(膜翅目:蚁科)记述

记述中国蚁科昆虫1新纪录属——支蚁属Cladomyrma Wheeler,W.M.1920及1中国新纪录种——岩支蚁Cladomyrma scopulosa Eguchi&Bui,2006。文中对新纪录属种进行描述,并提供了该新纪录种的高清彩图。

干河隧道围岩分级及初支参数选取

随着公路隧道的大量建设,其理论研究及施工创新也得到到迅猛的发展,对围岩分级准确性和衬砌参数合理性的要求均会越来越高。目前国内公路隧道主要以新奥法为基本设计理念。即隧道设计时,充分发挥围岩自身的承载能力,并在此基础上进行初期支护设计及二次衬砌设计。依托干河隧道对公路隧道围岩分级与初期支护参数选取的实践与应用进行分析。

采场老顶岩梁破断过程

为研究采场老顶岩梁破断过程,将初始来压前后的采场老顶岩梁简化为固支岩梁与悬臂岩梁.采用花岗岩作为试验材料对采场初始来压和周期来压的老顶岩梁进行了试验模拟,结合自主研发的基于拉张破坏准则的有限元开裂包对岩梁破断进行了数值分析.结果表明:固支岩梁在均布载荷下,破坏过程分为两个阶段:裂纹首先在端部萌生阶段和岩梁中间区域裂纹萌生阶段;固支岩梁端部裂纹的扩展方向与岩梁的高度和长度比值有关,而中部裂纹扩展方向始终垂直于轴线方向;悬臂岩梁的裂纹只产生在端部,裂纹的扩展方向与岩梁的长度和高度的比值有关;随着固支岩梁的裂纹逐渐扩展,岩梁的固支部分减少,不平衡力增加,岩梁的裂纹扩展速度加快.

膨涨性岩层内开鑿巷道其支保方式及支保结构的研究

抚顺煤田进行改建设计时,在西露设计中遇着膨涨性岩层——凝灰岩——的处理,在矿井中遇着不可能避免的巷道需开鑿在凝灰岩层内,因此为了使巷道能长期的维护使寿命达到30年的期限,故从节约出发,有必要对这样岩层中的巷道——支保——结构——进行研究,方能免除国家资金无益的损失。本文对露天的凝灰岩处理——用疏干巷道进行疏水,不作研究,仅对井工巷道提出初步的意见,供设计者研究。本文除情况介绍及个人肤浅的意见外,着重叙述苏联专家——柯里缅克——提供的意见。

充填率对充填开采覆岩应力分布的影响分析

为了研究充填回采过程中充填率对覆岩应力分布的影响规律,以某矿31041工作面为例,利用FLAC3D数值模拟软件对不同充填率下工作面支承压力分布进行模拟分析。结果表明,随着充填比的增大,支承压力影响范围减小,且集中应力峰值也不断减小;与放顶煤开采相比,回填开采能有效降低工作面前方的应力集中。

顺层偏压不良地质隧道边墙围岩大变形侵限处治方案研究

本文以新建磨万铁路旺门村1#隧道为例,介绍了因顺层偏压不良地质情况引起的隧道边墙围岩大变形和初支侵限的原因分析和工程技术处理方案。

Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

Due to the long-term plate tectonic movements in southwestern China,the in-situ stress field in deep formations is complex.When passing through deep soft-rock mass under non-hydrostatic high in-situ stress field,tunnels will suffer serious asymmetric deformation.There is no available support design method for tunnels under such a situation in existing studies to clarify the support time and support stiffness.This study first analyzed the mechanical behavior of tunnels in non-hydrostatic in-situ stress field and derived the theoretical equations of the ground squeezing curve(GSC)and ground loosening curve(GLC).Then,based on the convergence confinement theory,the support design method of deep soft-rock tunnels under non-hydrostatic high in-situ stress field was established considering both squeezing and loosening pressures.In addition,this method can provide the clear support time and support stiffness of the second layer of initial support.The proposed design method was applied to the Wanhe tunnel of the China-Laos railway in China.Monitoring data indicated that the optimal support scheme had a good effect on controlling the tunnel deformation in non-hydrostatic high in-situ stress field.Field applications showed that the secondary lining could be constructed properly.

SVM method for predicting the thickness of sandstone

The Support Vector Machine （SVM） method can be used to set up a nonlinear function prediction model. It is based on the small sample learning theory. The kernel function can be constructed automatically based on the actual sample data by using the SVM method. As a result, the function not only gets a higher fit precision but is also better generalized. The frequency spectrum and seismic waveform are related by Fourier transform, so they are two different forms of the same physical phenomenon. The variety of waveform character reflects stratigraphic differences and frequency spectrum differences reflect the variation of lithology, fluid composition, and formation thickness. It directly predicts sandstone thickness using the seismic waveform. This not only fully utilizes the seismic information but also greatly increases the accuracy of the prediction. Model examples and actual applications show the applicability of this method.

Support vector machines approach to mean particle size of rock fragmentation due to bench blasting prediction

Aiming at the problems of the traditional method of assessing distribution of particle size in bench blasting, a support vector machines （SVMs） regression methodology was used to predict the mean particle size （X50） resulting from rock blast fragmentation in various mines based on the statistical learning theory. The data base consisted of blast design parameters, explosive parameters, modulus of elasticity and in-situ block size. The seven input independent variables used for the SVMs model for the prediction of X50 of rock blast fragmentation were the ratio of bench height to drilled burden （H/B）, ratio of spacing to burden （S/B）, ratio of burden to hole diameter （B/D）, ratio of stemming to burden （T/B）, powder factor （Pf）, modulus of elasticity （E） and in-situ block size （XB）. After using the 90 sets of the measured data in various mines and rock formations in the world for training and testing, the model was applied to 12 another blast data for validation of the trained support vector regression （SVR） model. The prediction results of SVR were compared with those of artificial neural network （ANN）, multivariate regression analysis （MVRA） models, conventional Kuznetsov method and the measured X50 values. The proposed method shows promising results and the prediction accuracy of SVMs model is acceptable.

A Probabilistic View of Debris Flow

Most debris flows occur in valleys of area smaller than 50 km2. While associated with a valley, debris flow is by no means a full-valley event but originates from parts of the valley, i.e., the tributary sources. We propose that debris flow develops by extending from tributaries to the mainstream. The debris flow observed in the mainstream is the confluence of the tributary flows and the process of the confluence can be considered as a combination of the tributary elements. The frequency distribution of tributaries is found subject to the Weibull form (or its generalizations). And the same distribution form applies to the discharge of debris flow. Then the process of debris flow is related to the geometric structure of the valley. Moreover, viewed from a large scale of water system, all valleys are tributaries, which have been found to assume the same distribution. With each valley corresponding to a debris flow, the distribution can be taken as the frequency distribution of debris flow and therefore provides a quantitative description of the fact that debris flow is inclined to occur at valley of small size. Furthermore, different parameters appear in different regions, suggesting the regional differentials of debris flow potential. We can use the failure rate, instead of the size per se, to describe the risk of a valley of a given area. Finally we claim that the valleys of debris flow in different regions are in the similar episode of evolution.

Three-dimensional strata movement around coal face of steeply dipping seam group

Steeply dipping seam group, which has complex occurrence conditions, belongs to the steeply dipping seam. The research on the strata movement around the coal face not only improves safe production technology in practice, but also develops the mining theory. By using physical simulation experiments, numerical simulation and site test, the deformation, failure and movement of surrounding rock in Iongwall working face were analyzed. According to the analysis, characteristics of the seam group were formed which is different from the single seam. Asymmetry mechanics, sequential changes and imbalance of strata movement along the tendency working face were summarized. Furthermore the features of upper and lower seams were different. The mining of the lower seam induced more complex strata movement along the strike. Multi-section mining disturbed surrounding rocks in larger areas than the single section mining did, which had an impact on and dynamic loading function to the support when mining the lower seam, and produced a great influence on the stability of support-rock system.

Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress

In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.

Characteristics of soure region and tectonic implications of Early Indosinian Weiya gabbroic rock,eastern Tianshan mountains

Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.

Support failure of a high-stress soft-rock roadway in deep coal mine and the equalized yielding support technology： a case study

Abstract There are many soft-rock roadway coal mines in China. The surrounding rocks of the high-stress soft-rock roadways in deep mine are especially difficult to be supported using the traditional supporting way. In this study, the south wing rail roadway on the second level of Yunjialing coal mine in China was used as an example to analyze the deformation and failure characteristics and influencing factors of roadway. On this basis, this study proposed the equalized yielding support idea which employs the yielding rings to realize the pressure equalization on the bolts and cables in the section. To achieve this purpose, the first bolt-mesh-cable equalizing pressure yielding support was integrated with the second grouting reinforcement. The results proved that the yield rings of the bolts and cables on the spandrel of the arched roadway firstly developed yielding deformation; then the deformation extended to the vault of the roadway; the bolts and cables achieved a yielding extreme value of 15 and 18 tonnes, respectively. The roadway surrounding rock tended to be stable at the 26th day after the maintenance. The equalizing pressure yielding supporting technology plays a moderate pressure-releasing and actively controlling role on the surrounding rocks in the soft-rock roadway with large deformation.

Mechanism of rock deformation and failure and monitoring analysis in water-rich soft rock roadway of western China

Aiming to get the strata behavior and stability rules of surrounding rock of the main return airway of Yushujing Coal Mine, convergence deformation of two sides and force of U-shaped steel yieldable support and bolt were monitored, and deformation of surrounding rock and mechanical characteristics of support structure were timely obtained to guide the informa- tion construction and optimize supporting parameters in water-rich soft rock roadway. The field monitoring results indicate the following. （1） Convergence displacement of rock surface increases with time continuity and shows surrounding rock＇s intense theological behavior. The original support scheme cannot control the large deformation and strongly theological behavior; （2） Without backfilling, the U-shaped steel support begins to bear load after erecting for 4-7 days and increases rapidly in the first 30 days. The U-shaped steel support at the right shoulder and top of roadway bears a larger force and the left side and shoulder bears a smaller force; （3） The stress of bolt increasing over time and at the right shoulder of roadway has larger growth and value. The mechanism of rock deformation and the failure and strata behavior in water-rich soft rock roadway are revealed based on the results of the measured relaxation zone of surrounding rock, measured stresses, and the rock mechanics tests.

Study on strata control by delay grouting in soft rock roadway

The properties of broken rock before and after grouting reinforcement are studied. Testing results show that grouting can raise the residual strength of broken rock, and the broken rockness by grouting can keep the steady supporting capacity within a relatively large deformation range. Revealing of the characteristics of stage deformation and damage process comes to the conclusion that the supporting of soft rock roadway should be analyzed in a dynamic view, and the grouting should be delayed at a proper occasion. Based on the above, the stepwise reinforcement technology characterized by immediate shotcreting, timely bolting and delay grouting is put forward and illustrated with a successful engineering practice.

THE THEORY OF SUPPORTING BROKEN ZONE IN SURROUNDING ROCK

The first topic discussed in this paper is to evaluate the present supporting theories,among which the typical two are collapse arch and elasto-plastic theories. The former is rather limited in practical application,and the latter is built up on some assumptions which is inconsis-tent with the reality,for it is of no need to support a roadway of which the surrounding rock is in elasto-plastic state. The second topic is to prove the objective existence of the broken zone in surrounding rock(BZSR) by a series of laboratory experiments and field measurements. The paper indicates that the object to be supported mainly is the bulking or expanding force resulted from the development of BZSR. This is remarkably different from the existing points of view which have been generally recognized nowadays. So far ,this theory has been tested in supporting more than ten thousand meters roadways located in various strata and has proved itself to have a great technoeconomical benefit.

Parameter analysis of anchor bolt support for large-span and jointed rock mass

In order to obtain the optimal parameters of anchor bolt supporting system for large-span and jointed rock mass in Kaiyang Phosphor Mine, it is expensive and unavailable with the method of in-situ experiments. This paper describes a numerical modeling with discrete element method for the supporting effects of different type of anchor bolts. The anchor bolts with variant length of 0.5m, 0.8m, 1.0m, diameter of 10mm, 15mm, 20mm, setting spacing of 3.0m, 2.5m, 2.0m, and setting angle of 10°, 20°, 30°, are simulated respectively. The results show that there exist optimal parameters of anchor bolt support for large-span and jointed rock mass. For the bolt support of the concerning, the optimal length is 2.53.5m, the diameter is 2535mm, the spacing is 0.50.6m, and the setting angle is 105°.

Support pressure assessment for deep buried railway tunnels using BQ-index

Estimation of support pressure is extremely important to the support system design and the construction safety of tunnels.At present,there are many methods for the estimation of support pressure based on different rock mass classification systems,such as Q system,GSI system and RMR system.However,various rock mass classification systems are based on different tunnel geologic conditions in various regions.Therefore,each rock mass classification system has a certain regionality.In China,the BQ-Inex(BQ system)has been widely used in the field of rock engineering ever since its development.Unfortunately,there is still no estimation method of support pressure with BQ-index as parameters.Based on the field test data from 54 tunnels in China,a new empirical method considering BQ-Inex,tunnel span and rock weight is proposed to estimate the support pressure using multiple nonlinear regression analysis methods.And then the significance and necessity of support pressure estimation method for the safety of tunnel construction in China is explained through the comparison and analysis with the existing internationally widely used support pressure estimation methods of RMR system,Q system and GSI system.Finally,the empirical method of estimating the support pressure based on BQ-index was applied to designing the support system in the China’s high-speed railway tunnel—Zhengwan high-speed railway and the rationality of this method has been verified through the data of field test.

Research on sustenance of soft rock tunnel in Hongmiao Mine of Pingzhuang Mine Area

The return airway tunnel of bank 6 is an important tunnel for air return and auxiliary transportation.While under construction,the tunnel was seriously deformed, and the bottom was heavily squeezed.When completed,the bottom was smoothed out several times and a lot of maintenance were done.But about half year later,the tunnel collapsed.To counter the problems mentioned above,we systematically expounded our ideas and designed for solving the problem of the sustenance of the return airway tunnel of section 6.