西矿区深海稀软底质剪切强度和贯入阻力原位测试

In-situ shearing strength and penetration resistance testing of soft seabed sediments in western mining area

为获得深海稀软底质的力学参数及其相关经验公式,采用原位测试的方法,基于十字板剪切和浅层静力触探试验,在东太平洋中国开辟区西矿区的深海稀软底质进行剪切强度和贯入阻力测试,获得41个测点的测量数据。测量结果表明:剪切强度和贯入阻力在峰值强度前随试验深度的增加而增大,峰值强度后小幅度降低,其峰值强度均出现在40～45 cm层,分别为11.8 kPa和100 kPa;0～8 cm层底质的抗剪性能和承压性能极差,无工程意义;14～20 cm层底质的抗剪性能和承压性能均匀,剪切强度从6 kPa缓慢降低至5.8 kPa,贯入阻力从46 kPa缓慢增加至50 kPa,可作为行走履带的剪切牵引层和持力层,履齿应全部或部分落在14～20 cm层,齿高至少应为6 cm,作用于履齿的剪切强度设计值为3～4 kPa,履带板下陷后的位置应在14 cm以下。建立的回归经验公式能客观反映底质的抗剪特性和承压特性,可为集矿机的设计尤其对行走履带和接地比压的确定提供理论依据。

To obtain the mechanics parameters of the soft deep seabed sediments,the shearing strength and penetration resistance tests were made in Chinese ＂Pioneer Area＂ in the western part of the Pacific with the in-situ testing way.According to the measured data in the 41 sites,the shearing strength and penetration resistance increase with the increase of testing depth till their own peak values then go down in small range.The shearing strength and penetration resistance are very low in the depth from 0 cm to 8 cm and reach their respective peak values in the depth of 40-45 cm,which are 11.8 kPa and 100 kPa,respectively.The soil in the depth 14-20 cm can be used to traction and bear the tracked vehicle because of its homogeneous mechanics characteristic with shearing strength of 5.8 kPa and penetration resistance varying from 46 kPa to 50 kPa.Tooth should work in the depth from 14 cm to 20 cm with the lowest height of 6 cm and the design value of shearing strength around the tooth should be 3-4 kPa.The track shoe should sink to the depth of 14 cm in the stationary state.Four empirical formulas based on the above data can be used to evaluate shearing strength and bearing behavior of the soft deep seabed sediments.The formulas may be used to design the track of the seabed tracked vehicle,especially to determine its grouding pressure.