Design of comprehensive test system for detecting overlying strata mining-induced fractures on surface with radon gas

Based on radon gas properties and its existing projects applications, we firstly attempted to apply geo- physical and chemical properties of radon gas in the field of mining engineering, and imported radioac- tive measurement method to detect the development process of the overlying strata mining-induced fractures and their contained water quality in underground coal mining, which not only innovates a more simple-fast-reliable detection method, but also further expands the applications of radon gas detection technology in mining field. A 3D simulation design of comprehensive testing system for detecting strata mining-induced fractures on surface with radon gas (CTSR) was carried out by using a large-scale 3D solid model design software Pro/Engineer (Pro/E), which overcame three main disadvantages of ''static design thought, 2D planar design and heavy workload for remodification design'' on exiting design for mining engineering test systems. Meanwhile, based on the simulation design results of Pro/E software, the sta- bility of the jack-screw pressure bar for the key component in CTSR was checked with a material mechan- ics theory, which provided a reliable basis for materials selection during the latter machining process.

A comprehensive testing method for global stability analysis of high arch dams

Hydropower projects are rapidly developing in China at present, and a number of high daras and large reservoirs are currently under construction or will soon be built. These large projects are mainly located on the great rivers in West China with complicated topographical and geological conditions. Evaluation of stability and safety of these high dam projects is an important topic. Geomechanical model test is one of the main methods to study the global stability of high dam and foundation. In this paper, a comprehensive testing method that combines overloading and strength reduction in a model is proposed. In this method, both the influence of excessive flooding and the effects of strength reduction of rock masses and weak structural planes on dam stability are considered. Thus, the comprehensive testing method can accurately incorporate multiple factors that affect the global stability of high dam and its foundation. Based on the failure testing principle and model similarity theory, a similarity relation formula for safety evaluation through comprehensive test is established. A new model material, temperature-dependent analogous material, is also developed. By rising the temperature and reducing the strength of the mod,~l material, the mechanical behaviors resulting from gradual strength reduction can be simulated. Thus, the comprehensive testing method is realized in a single model. For case studies, the comprehensive geomechanical model test is conducted for Jinpinlg I and Xiaowan high arch dam projects.

Comprehensive Multi-Level Exploration of Buried Active Faults:an Example of the Yinchuan Buried Active Fault

The paper introduces the steps and methods of multi-approach, multi-level exploration of buried faults in thick Quaternary sediment regions by taking the test exploration of the Yinchuan active fault as example. Based on the comprehensive analyses of previous data, we choose the Xinqushao Village of Xingqing District of Yinchuan City as the test site for the comprehensive exploration. Firstly, we adopted shallow seismic investigation with group intervals of 10m, 5m and lm to gradually trace layer by layer the master fault of the Yinchuan buried fault from a deep depth to a shallow depth where drilling could be used. Then, with composite geological profile drilling, we determined the precise location and dip angle of the fault. The drilling show the buried depth of the upper offset point is 8.3m. Finally, large-scale trenching revealed that the actual buried depth of the upper offset point of the fault is 1.5m from the ground surface and there are paleoearthquake events of 5 stages. Combined with the preliminary result of corresponding sample age, we conclude the Yinchuan buried fault is a mid to late Holocene active fault.

Exclusive Hypothesis Testing for Cox's Proportional Hazards Model

Exclusive hypothesis testing is a new and special class of hypothesis testing.This kind of testing can be applied in survival analysis to understand the association between genomics information and clinical information about the survival time.Besides,it is well known that Cox's proportional hazards model is the most commonly used model for regression analysis of failure time.In this paper,the authors consider doing the exclusive hypothesis testing for Cox's proportional hazards model with right-censored data.The authors propose the comprehensive test statistics to make decision,and show that the corresponding decision rule can control the asymptotic TypeⅠerrors and have good powers in theory.The numerical studies indicate that the proposed approach works well for practical situations and it is applied to a set of real data arising from Rotterdam Breast Cancer Data study that motivated this study.

A STUDY ON THE CONSTRUCT VALIDITY OF LONG DIALOGUE MULTIPLE-CHOICE LISTENING COMPREHENSION TESTS: RETROSPECTION APPROACH

This paper aims to explore the construct validity of long dialogue multiple-choice (MC) listening comprehension tests through examining the retrospective verbal reports of eight Chinese EFL test-takers at tertiary level. It is found that the grammatical knowledge, discourse knowledge, pragmatic knowledge and sociolinguistic knowledge of language competence and all the cognitive and metacognitive strategies proposed in the framework of listening constructs are measured in the tests, which supports the constr...

CONTENT VALIDITY STUDY ON READING COMPREHENSION TESTS OF NMET

Based on the framework of task characteristics' proposed by Bachman and Palmer (1999), this paper attempts to explore the characteristics and content validity of reading comprehension tests of NMET. By comparing and analyzing the data carefully, the author concludes that reading comprehension parts of NMET have well met the requirements in the two syllabi and have reached a high content validity. However, the author detects some weaknesses and puts forward some suggestions with the purposes for further improving and developing the future reading tests.