The penetration effects of projectiles impacting rocks are of great significance in the underground protective engineering and the weapon warhead designs. Especially，issue of the overload of the projectiles is more essential as the key technology for the warhead designs，but also great help to make a clear definition of the motion laws of the projectile and the interactions between projectiles and the rock targets. In order to study the overload characteristics of projectiles penetrating rocks，rock-penetrating experiments were carried out using projectiles with diameters f 100 mm and f 300 mm，respectively. The overload versus time curve was recorded by means of an overload measurement system. Based on the overload curves，the projectiles¢ overload can be divided into three phases：the overload of rapid increasing as the contact area increases；the overload reducing slowly after the nose enters the targets；and the overload reducing rapidly to zero when the projectile¢s energy is almost used up. From the achieved overload curves，it can be obtained that the projectiles have the peak overloads when the penetration depths come up to two times the diameter of projectile. The rocks around the projectile¢s nose are damaged due to the stress wave of penetration，and then，the targets have less ability to prevent the projectilesmotion. On the basis of the experimental results，a new formula of penetration depth has been presented here with reference to experimental data of other tests. The precision is not lower within certain range in comparison with the widely accepted Young¢s formula. Numerical simulation is in good agreement with the experimental results.

With the development of geomechanics and the requirements of many large-scale engineering projects，soil-rock mixtures(SRM) have been regarded as a special type of soil and rock materials which are substantially different with the general soils and rocks in geotechnical engineering. In a large extent，the proportion and distribution of the rock block sizes control the physico-mechanical properties of SRM. Using digital image processing，rock block sizes in SRM samples are identified from the soil matrix. The proportion and distribution of the rock block sizes are then obtained quantitatively. Then the results are used for the sample preparation of the large scale direct shear tests，which cuts a new method for the test study of SRM. According to the results of the large scale direct shear tests，as a whole，the rock block size proportion controls the deformation and fracture mechanism of SRM. The shape of the shear stress versus the horizontal displacement curve and the vertical displacement versus the horizontal displacement curve of the remolded SRM samples are different from the general soils and rocks. With the increase of the rock block proportion，the shear band of SRM increased. When the rock block proportion lied in the range of 25% to 70%，the increment of the internal frication angle increased linearly with the increase of the rock block proportion. And the cohesion of the SRM decreased largely from the soil matrix. When the rock block proportion is large than 30%，however，there is only a little decrease in the cohesion with the increase of the rock block proportion.

Soil liquefaction is a major concern for structures constructed on sandy and silty sites. Soil liquefaction is also a major design issue for large structures such as mine tailings impoundments and earth dams. Therefore，liquefaction evaluation plays an important role in seismic investigation and design of buildings. It is important to determine the soil stratigraphy and in-situ soil state for soil liquefaction. Because of the difficulty and cost constraint of obtaining high-quality undisturbed sand samples，the in-situ test is a perfect method to evaluate the potential for soil liquefaction. At present，numerous methods based on the cone penetration test(CPT) data have been developed for evaluating the potential of soil liquefaction，but the validity is still confused. As a new kind of in-situ test，the piezocone penetration test(CPTU)，is receiving increasing attention for assessing the soil liquefaction potential because of its repeatability，reliability，continuous data tracing and cost effectiveness. The methods for evaluating liquefaction potential of soils using in-situ tests are reviewed based on the precious works. Two comprehensive CPTU-based methods for assessing liquefaction resistance of sandy soils are evaluated and compared on the basis of data collected on nine sites in Jining—Xuzhou Expressway，where the actual field performances against liquefaction from CPT data are used as referenced data. It is shown that Robertson method and Olsen method are considered to be fairly accurate in predicting liquefaction resistance of sandy soils. The Robertson method is slightly more accurate than the Olsen method.