Calcium Carbonate Growth with the Ring Structure of Stalactite-Type Minerals in a Tuff Breccia

Microbially induced carbonate precipitation (MICP) has attracted worldwide attention as an environmentally friendly ground restoration technology in response to geohazards. This study describes the relationship between calcium carbonate growth within stalactite-type minerals formed around fractures in tuff breccia and microorganisms. Scanning electron microscopy revealed that calcium carbonate was precipitated in the interstices of rings formed in stalactite-type minerals, as if the carbonate minerals enhanced the strength of the silicate minerals. In addition, X-ray powder diffraction analysis detected that the calcium carbonates were calcite and vaterite. Moreover, microorganisms, such as diatoms and green algae, inhabited the interstices and, consequently, MICP by these microorganisms could play a role in the stability of outcrops. The stable isotope ratios of δ13C and δ15N and the mass spectral signals of the demineralized samples also encouraged diatoms and green algae to be involved in the formation of minerals.

PSIV-10 The Effect of a Dacitic (rhyolitic) Tuff Breccia, a Hydrated Sodium Calcium Aluminosilicate (HSCAS), Inclusion in Corn-soybean Meal Diets on Growth Performance of Individually Housed Grower Pigs

Crossbred pigs (24 barrows and 24 gilts; BW 35.59±0.24 kg) were blocked by body weight, sex, and allotted in a randomized complete block design to 3 dietary treatments: 1) Control [CON], 2) CON+0.25%, and 3) CON+0.50% inclusion of a dacitic tuff breccia (DTB) to evaluate effects on growth performance. Diets were formulated to meet or exceed NRC (2012) requirement estimates and fed for 2 phases (d0-14=PHS_1 and d14-28=PHS_2). Diets were limit fed based on metabolic body weight (3.5 x maintenance ME needs [3.5 × 106 Kcal ME/kg BW0.75]). Pigs were weighed weekly and feed allowance adjusted accordingly. In PHS_1, a tendency for a sex difference, gilt vs. barrow, respectively, for ADG (4.92%; 0.913 vs. 0.870 kg; P=0.10) and G:F (4.14%; 0.528 vs. 0.507; P=0.06) existed. The responses to treatments 1–3, respectively, for ADG (0.877, 0.900, and 0.896 kg; linear P=0.54) and G:F (0.510, 0.522, 0.521; linear P=0.46) were numerically greater. In PHS_2, sex differences, gilt vs. barrow, respectively, for ADG (5.67%; 0.946 vs. 0.895 kg; P=0.05) and G:F (7.98%; 0.460 vs. 0.426; P< 0.01) existed. The numerical responses to treatments 1–3, respectively, for ADG (0.912, 0.944 and 0.905 kg; P=0.41) and G:F (0.439, 0.446, 0.444; linear P=0.70) continued. A tendency for a quadratic response in ADFI (P=0.06) existed because feed allowance increased with increasing weekly BW for treatments 2 and 3. Overall, sex differences, gilt vs. barrow, respectively, for ADG (5.30%; 0.929 vs. 0.882 kg; P< 0.05) and G:F (6.23%; 0.491 vs. 0.462; P< 0.01) occurred. Numerical responses to treatments 1–3, respectively, for ADG (0.895, 0.921 and 0.900 kg, P=0.32) and G:F (0.471, 0.480, 0.479; linear P=0.50) occurred. Additionally, the response to DTB appeared to be higher in barrows.

PSVI-17 The Effect of Dacitic Tuff Breccia Alone or in Combination with Poultry By-products on Nursery Pig Growth Performance

Dacitic tuff breccia (DTB) and poultry by-products (PBP) were added to nursery pig diets to evaluate their effects on growth performance in a 35 d experiment. A randomized complete block design based on BW and sex was used. Newly weaned pigs (N=564, 20.1 d of age, 6.18±0.006 kg initial BW) allotted to four diets (15 replicates/treatment; 9 or 10 pigs/pen): 1) Negative control (NC; no DTB or PBP), 2) NC+DTB (0.5% inclusion), 3) NC+PBP (4% chicken by-product meal + 2% feather meal – replacing fishmeal, corn, and synthetic amino acids in the NC), 4) NC+DTB+PBP. Phase 1–3 were each 7-d and Phase 4 was from d21-35. During week one there were no differences (P >0.10) among treatments. In week 2, pigs fed DTB tended to increase ADG (323 vs. 303 g/d; P=0.068) and ADFI (376 vs. 356 g/d; P=0.055) compared to pigs not fed DTB and pigs fed PBP tended to have increased ADG (P=0.093). In week 3 pigs fed PBP had reduced ADG (460 vs 483 g/d; P=0.011) and G:F (0.689 vs. 0.723; P< 0.001), and there tended to be an interaction for G:F (P=0.083) with DTB improving G:F when fed in combination with PBP but reducing G:F in the control diet. In week 4, feeding PBP decreased ADG (384 vs 415 g/d; P< 0.01) and ADFI (629 vs 666 g/d; P< 0.01) compared to pigs fed no PBP. There were no differences among treatments during week 5. For Phase 4 (d21-35) pigs fed PBP had decreased ADG (479 vs 497 g/d; P=0.041) and tended to have reduced ADFI (P=0.092) compared to pigs fed no PBP. Overall (d 0–35), there were no significant differences among treatments. In conclusion, DTB improved nursery pig growth performance early, however, pigs fed PBP had decreased ADG and feed efficiency late in the nursery period.

Frictional stability of porous tuff breccia under subsurface pressure conditions and implications for shallow seismicity

Thick sediment layers frequently cover the Japan islands’ surface, and their frictional properties significantly affect the shallow slip behavior that occurs during earthquakes. However, laboratory data on the properties of the shallow zone remain limited. We collected tuff breccia samples from deep borehole cores in the Miocene “Green Tuff” formation, a major surface cover, and performed velocity-stepping friction tests on these samples under in situ stresses of 2 to 20 MPa to assess the velocity dependence of their frictional strength. The samples exhibit predominantly frictionally stable, velocity-strengthening behavior over the range of normal stresses tested, which supports the hypothesis that shallow sediment layers are seismically quiescent. This result is consistent with the low seismicity and attenuation of coseismic slip occurring in the shallow zone that is observed during regional earthquakes. Microstructural observations of the postmortem samples using optical and scanning electron microscopes indicate a fabric transition from boundary shear localization to distributed cataclastic flow with increasing normal stress. Our laboratory investigation of the depth-variable distribution of the frictional velocity dependence of a shallow sediment layer would provide further insight into the mechanical role for earthquake rupture dynamics and shallow seismicity.

Characteristics of tuff breccia-andesite in diverse mechanisms of landslides in Oita Prefecture, Kyushu, Japan

Heavy rainfall frequently occurred in Kyushu and triggers the landslides every year. This study observes the landslides which occurred in Oita Prefecture, Kyushu, Japan. The landslides in this study, consisting of the same soil materials, tuff breccia and andesite materials; however, the landslide mechanisms were different. Two landslides occurred caused by heavy rainfall in the different timing of the landslide occurrence, and another landslide occurred without the heavy rainfall or an earthquake occurs. Therefore, this study aims to analyse the physical and mechanical properties of tuff breccia and andesite materials with diverse landslide mechanisms. This study performed soil stratigraphic analysis and soil hardness measurements in the field, and performed physical properties, saturated permeability, mechanical properties, and XRD tests in the laboratory. This study found that characteristics of tuff breccia and andesite in diverse mechanisms of landslides were not very different, especially on the landslides caused by heavy rainfall. Furthermore, the landslide in the andesite and tuff breccia areas could be divided into three types based on the timing of the landslide occurrence, scale of the landslide, and landslide mechanisms.

Frictional Stability of Porous Tuff Breccia Under Subsurface Pressure Conditions and Implications for Shallow Seismicity

Thick layers of unconsolidated sediments are widespread in the Japan island’s surface, and their frictional properties significantly affect the shallow slip behavior during earthquakes. However, laboratory data on the properties of the shallow zone remain limited. We collected tuff breccia samples from deep borehole cores of the Miocene “Green Tuff” formation, a major surface cover, and performed velocity-stepping friction tests on them under in situ stresses of 2 to 20 MPa to assess the velocity-dependence of frictional strength. The samples exhibit predominantly frictionally stable, velocity-strengthening behavior over the range of normal stress tested, which supports the hypothesis that shallow sediment layers are seismically quiescent. The result is consistent with the low seismicity and attenuation of coseismic slip in the shallow zone observed for the regional earthquakes. Microstructural observations of the postmortem samples through optical and scanning electron microscopies indicate a fabric transition from boundary shear localization to distributed cataclastic flow with increasing normal stress. Our laboratory investigation on depth-variable distribution of friction velocity dependence of a shallow sediment layer would provide further insight into the mechanical role for earthquake rupture dynamics and shallow seismicity.

Engineering geological characterisation of rock masses for design of excavation method and support system of Tanju Tunnel, West Nusa Tenggara, Indonesia

This paper presents experiences with design and construction process of the Tanju Tunnel, West Nusa Tenggara. The objective of this research was to characterize the volcanic and intrusive rock masses for designs of the tunnel excavation method and support system. Engineering geological investigations were carried out, upon which the tunnel stand-up time was estimated and the tunnel excavation method and support system were determined based on the rock mass classifications of RMR (Bieniawski, 1989). The investigation results showed that the tunnel construction area consisted of colluvium, andesite, and tuff breccia. The rock masses were dominated by the andesite, which had UCS of intact rock ranging from 200 to 300 MPa classified as strong intact rock. Based on the RMR value, the andesite was classified as a good quality rock mass. The tunnel had unsupported roof stand-up time approximately 20.000 hours for a 3 m tunnel span. The recommended tunnel excavation method was full face, 1.0-1.5 m advance, and complete support 20 m from face, while the support systems were locally bolt in crown 3 m long and 2.5 m spacing, with occasional wire mesh, 50 mm thick shotcrete in crown where required.